Summary of Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	The consolidated financial statements have been prepared in accordance with the generally accepted accounting principles in the United States (“GAAP”)
Consolidation	The consolidated financial statements have been prepared in accordance with the generally accepted accounting principles in the United States (“GAAP”) and include the accounts of Frontier Group Holdings, Inc. (“FGHI” or the “Company”) and its wholly-owned direct and indirect subsidiaries, including Frontier Airlines Holdings, Inc. (“FAH”) and Frontier Airlines, Inc. (“Frontier”). All wholly-owned subsidiaries are consolidated, with all intercompany transactions and balances being eliminated. The Company is an ultra low-cost, low-fare airline headquartered in Denver, Colorado that offers flights throughout the United States and to select international destinations in the Americas, serving approximately 100 airports. The Company is managed as a single business unit that provides air transportation for passengers and management has concluded there is only one reportable segment. See Passenger Revenues and Other Revenues within this note for additional information on the services from which the Company derives its revenues. The Company has identified its Chief Executive Officer and President, as its chief operating decision makers (“CODMs”). The CODMs primarily use net income to evaluate the strategic direction and assess performance of the Company. This metric is used to evaluate budget versus actual results on a regular basis and make resource allocation decisions to optimize and assess performance of the Company’s consolidated financial results. Please see the Company’s “Consolidated Statements of Operations” for net income, as well as other significant revenue and expense components of profit or loss, for the years ended December 31, 2024, 2023 and 2022. Please see the Company’s “Consolidated Balance Sheets” for total assets as of December 31, 2024 and 2023. Reclassifications Certain reclassifications of previously reported amounts have been made to conform to the current year presentation within the corporate tax rate reconciliation table and the net deferred tax asset (liability) table in Note 15. Income Taxes. These reclassifications did not impact previously reported amounts on the Company’s consolidated balance sheets, consolidated statements of operations, consolidated statements of comprehensive income (loss), consolidated statements of cash flows or consolidated statements of stockholders’ equity.
Use of Estimates	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results could differ from those estimates.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of acquisition to be cash and cash equivalents. Additionally, any items with maturities greater than three months that are readily convertible to known amounts of cash are considered cash and cash equivalents. Investments included in this category primarily consist of money market funds and time deposits. Restricted Cash Restricted cash includes cash to secure medical claims paid. The Company also has covenant requirements with certain of its lenders which require cash to be deposited at the end of each quarter into a lockbox until the Company certifies that it is in compliance with its covenants.
Accounts Receivable, net	Receivables primarily consist of amounts due from credit card receivables, amounts due from select airport locations under revenue share agreements and amounts due from Barclays as part of the Company’s credit card affinity agreement. The Company records an allowance for credit losses for amounts not expected to be collected. The Company estimates the allowance based on expected credit losses.
Supplies, net	Supplies consist of expendable aircraft spare parts, aircraft fuel and other supplies and are stated at the lower of cost or net realizable value. Supplies are accounted for on a first-in, first-out basis and are charged to expense as they are used. An allowance for obsolescence on expendable aircraft spare parts is provided over the remaining lease term or the estimated useful life of the related aircraft fleet to reduce the carrying cost of spare parts currently identified as excess to the lower of amortized cost or net realizable value.
Property and Equipment, net	Property and equipment are stated at cost and depreciated on a straight-line basis over their estimated useful lives to their estimated residual values. The Company capitalizes additions, modifications enhancing the operating performance of its assets and the interest related to payments used to acquire new aircraft and the construction of its facilities. The Company capitalizes interest attributable to pre-delivery deposit payments (“PDPs”) as an additional cost of the related asset beginning when activities necessary to get the asset ready for its intended use commence. The Company capitalizes certain internal and external costs associated with the acquisition and development of internal-use software for new products and enhancements to existing products that have reached the application development stage and are deemed feasible. The Company depreciates these costs using the straight-line method over the estimated useful life of the software. Capitalized costs include external direct costs of materials and services utilized in developing or obtaining internal-use software, and labor cost for employees who are directly associated with, and devote time to, internal-use software projects.
Leases	The Company leases property and equipment under operating leases. For leases with initial terms greater than 12 months, the related operating lease right-of-use asset and corresponding operating lease liability are recorded at the present value of lease payments over the term on the Company’s consolidated balance sheets. Some leases include rental escalation clauses, renewal options, termination options and/or other items that cause variability that are factored into the determination of lease payments when appropriate. The Company does not separate lease and non-lease components of contracts, except for certain flight training equipment, for which consideration is allocated between lease and non-lease components. When available, the rate implicit in the lease is used to discount lease payments to present value; however, most leases do not provide a readily determinable implicit rate. Therefore, the Company estimates its incremental borrowing rate (“IBR”) to discount the lease payments based on information available at lease commencement. The IBR utilized by the Company is first determined using an unsecured recourse borrowing rate over a tenor that matches the period of lease payments for each individual lease and then is adjusted to arrive at a rate that is representative of a collateralized rate (secured rate). Given the Company does not have an established unsecured public credit rating, the Company utilizes current period and projected financial information to simulate an unsecured credit rating. The Company then determines its secured IBR using a combination of several valuation methods that take into account the lower amount of risk of collateralized borrowings along with observable implied credit ratings from its current outstanding secured debt obligations.
Forgivable Loans	Since 2022, the Company has launched several programs geared at attracting and retaining highly skilled pilots and mechanics. As an incentive of these programs, the Company issues forgivable loans to cadets and mechanics who join the programs, which can include pre-employment incentives such as a sign-on bonus, a monthly stipend, or reimbursement of training costs incurred. The loans and related interest are forgiven after a predetermined stay period, typically three years. Principal and interest incurred is to be repaid to the Company if a cadet or a mechanic terminates prior to the stay period being completed.
Asset Impairment	The Company applies a fair value-based impairment test to the carrying amount of indefinite-lived intangible assets annually, or more frequently if certain events or circumstances indicate impairment. The Company assesses the value of indefinite-lived assets under a qualitative and quantitative approach, as required. Under a qualitative approach, the Company considers various market factors. These factors are analyzed to determine if events and circumstances indicate that it is more likely than not that an indefinite-lived intangible asset's fair value is less than its carrying value. The quantitative approach is used to assess the asset’s fair value and the amount of the impairment. If the asset’s carrying amount exceeds its fair value calculated using the quantitative approach, an impairment charge is recorded for the difference in fair value and carrying amount. Indefinite-lived intangible assets are comprised of certain landing slot rights and the trademark of the Company. Factors that could result in future impairment of landing slot rights, holding other assumptions constant, include, but are not limited to: (i) significant reduction in demand for air travel, (ii) competitive activity in the slotted airport, (iii) anticipated changes to the regulatory environment such as diminished slot access and (iv) increased competition at a nearby airport. As part of this evaluation, the Company assesses whether changes in (i) macroeconomic conditions, (ii) industry and market conditions, (iii) cost factors, (iv) overall financial performance and (v) certain events specific to the Company, have occurred which would impact the use and/or fair value of these assets. Based on the Company’s qualitative analysis performed during the fourth quarter of 2024, the Company concluded it is more likely than not that the fair values of its indefinite-lived intangible assets are greater than the carrying amount. Therefore, a quantitative assessment was not necessary. No impairments have been recorded in any periods presented. Finite-lived intangible assets are comprised of the Company’s affinity credit card program relationship recognized in connection with acquisition accounting and are amortized over their estimated economic useful life. The Company records impairment charges on long-lived assets used in operations and finite-lived intangible assets when events and circumstances indicate that the assets may be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets, and the net book value of the assets exceeds their estimated fair value. In making these determinations, the Company uses certain assumptions, including, but not limited to: (i) estimated fair value of the assets; and (ii) estimated undiscounted future cash flows expected to be generated by these assets, which are based on additional assumptions such as asset utilization including macroeconomic factors impacting future demand, length of service the asset will be used in the Company’s operations and estimated salvage values.
Aircraft Maintenance	The Company accounts for heavy maintenance and major overhauls under the deferral method, whereby the cost of heavy maintenance and major overhauls is deferred and recorded as flight equipment and depreciated over the lesser of the remaining lease term or the period until the next scheduled heavy maintenance event. The Company has separate maintenance cost-per-hour contracts for the repair of certain rotable parts to support airframe and engine maintenance and repair. These agreements require monthly payments based upon utilization, such as flight hours, cycles and age of the aircraft. For the contracts in which risk has been determined to transfer to the service provider, expense is recognized based on the contractual terms of the cost-per-hour arrangement. For those contracts in which risk has not been determined to transfer to the service provider, the Company initially records monthly payments as a deposit included in other assets on the Company’s consolidated balance sheets and then accounts for the underlying maintenance event when it occurs, in accordance with the Company’s maintenance accounting policy. Previously, certain of the Company’s aircraft lease agreements required, and may again require in the future, the Company to pay maintenance reserves to aircraft lessors to be held as collateral in advance of the Company’s required performance of major maintenance activities. At lease inception and at each balance sheet date, the Company assesses whether the maintenance reserve payments required by its leases are substantively and contractually related to the maintenance of the leased asset. Maintenance reserve payments that are determined to be related to the maintenance of the leased asset are accounted for as maintenance deposits, to the extent they are expected to be recoverable, and are reflected as aircraft maintenance deposits on the Company’s consolidated balance sheets. As the eligible maintenance is performed, the maintenance deposits are recorded in accounts receivable, net on the Company’s consolidated balance sheets. When it is not probable that the Company will recover amounts on deposit with a lessor, such amounts are expensed as supplemental rent within aircraft rent in the Company’s consolidated statements of operations. Maintenance reserve payments that are based on a utilization measure and are not probable of being recovered are considered variable lease payments and are not included within the right-of-use asset and respective lease liability. During the year ended December 31, 2024, an agreement was reached with one of the Company’s aircraft lessors which eliminated requirement to pay maintenance reserves held as collateral in advance of the Company’s required performance of major maintenance activities on its aircraft leases. As a result, none of the Company’s current aircraft lessors require these payments to be held as collateral. When the Company is required to pay maintenance reserves to aircraft lessors, the Company makes certain assumptions at the inception of the lease and at each balance sheet date to determine the recoverability of maintenance deposits. These assumptions are based on various factors, such as the estimated time between the maintenance events, the cost of such maintenance events, the date the aircraft is due to be returned to the lessor and the number of flight hours and cycles the aircraft is estimated to be utilized before it is returned to the lessor. Changes in estimates are accounted for on a cumulative catch-up basis. On a regular basis, the Company assesses the credit worthiness of the Company’s lessors to ensure deposits are collectible and, specifically, whether any credit losses exist for aircraft maintenance deposits. Based on these assessments, the Company determined no allowance was necessary as of December 31, 2024 and 2023. Certain of the Company’s historical lease agreements have provided, and future lease agreements may provide, that maintenance reserves held by the lessor at the expiration of the lease are nonrefundable to the Company and will be retained by the lessor. Consequently, any usage-based maintenance reserve payments after the last major maintenance event would not substantively be related to the maintenance of the leased asset and, therefore, would be accounted for as supplemental rent.
Leased Aircraft Return Costs	The Company’s aircraft lease agreements generally contain provisions that require the Company to return aircraft airframes and engines to the lessor in a specified condition or pay an amount to the lessor based on the airframe and engine’s actual return condition. Lease return costs include all costs that would be incurred at the return of the aircraft, including costs incurred to repair the airframe and engines to the condition required by the lease. Lease return costs could include, but are not limited to, redelivery cost, redelivery crew cost, fuel, final inspections, reconfiguration of the cabin, repairs to the airframe, painting, overhaul of engines, replacement of components and checks. These return provisions are evaluated at inception of the lease and throughout the lease terms and are accounted for as either fixed or variable lease payments (depending on the nature of the lease return condition) when it is probable that such amounts will be incurred. When determining probability and estimated cost, there are various other factors which need to be considered such as current condition of the aircraft, the age of the aircraft at lease expiration, number of hours run on the engines, number of cycles run on the airframe, projected number of hours run on the engine at the time of return, the projected number of cycles run on the airframe at the time of return, the extent of repairs needed, if any, upon return, return locations, current configuration of the aircraft, current paint of the aircraft, estimated escalation of cost of repairs and materials at the time of return, current flight hour agreement rates and future flight hour agreement rates. In addition, typically near the lease return date, the lessors may allow maintenance reserves to be applied as return condition consideration or pass on certain return provisions if they do not align with their current plans to remarket the aircraft. As a result of the different factors listed above, management assesses the need to accrue lease return costs throughout the lease as facts and circumstances warrant an assessment. When costs become both probable and estimable, lease return costs are expensed as a component of aircraft rent in the Company’s consolidated statements of operations through the remaining lease term.
Derivative Instruments	The Company is party to certain interest rate swaption agreements that are accounted for as cash flow hedges, as defined under ASC 815, Derivatives and Hedging. Some of the Company’s aircraft and spare engine sale-leaseback agreements can expose it to interest rate risk as, depending on the agreement, rental payments are adjusted and become fixed based on the swap rate at the time of delivery. The primary objective for interest rate derivatives is to hedge the portion of the estimated future monthly rental payments related to the associated agreement’s variable interest rate, primarily the Secured Overnight Financing Rate (“SOFR”). These swaption agreements provide for a single payment at maturity based upon the change in the applicable swap rate between the execution date and the termination date. For interest rate derivatives, the Company recognizes the associated gains or losses deferred in accumulated other comprehensive income/(loss) (“AOCI/L”), as well as amounts that are paid or received in connection with the purchase or sale of interest rate derivative instruments (i.e., premium costs of swaption contracts), as a component of aircraft rent expense within the Company’s consolidated statements of operations over the period of the related aircraft lease. Cash flows related to interest rate swaption agreements are classified as operating activities in the Company’s consolidated statements of cash flows. The Company presents its interest rate swaption derivative instruments gross on the consolidated balance sheets. The Company does not enter into derivative instruments for speculative purposes.
Revenue	Fare revenues. Tickets sold in advance of the flight date are initially recorded as an air traffic liability on the Company’s consolidated balance sheets. Fare revenues are generally recognized in passenger revenues within the Company’s consolidated statements of operations at the time of departure when transportation is provided. Non-fare passenger revenues. Certain ancillary items such as service fees, baggage and seat selection deemed part of providing passenger transportation are recognized to non-fare passenger revenues in passenger revenues within the Company’s consolidated statements of operations at the time of departure. Service fees include, among other things, convenience fees, charges for nonrefundable ticket expiration, cancellation charges and service charges assessed for itinerary changes made prior to the date of departure. Such change fees are recognized at the time of departure of the newly scheduled travel. Passenger Taxes and Fees. The Company is required to collect certain taxes and fees from customers on behalf of government agencies and airports and remit these back to the applicable governmental entity or airport on a periodic basis. These taxes and fees include U.S. federal transportation taxes, federal security charges, airport passenger facility charges, and foreign arrival and departure taxes. These taxes and fees are collected from customers at the time they purchase their tickets but are not included in passenger revenues. The Company records a liability within other current liabilities on the consolidated balance sheets upon collection from the customer, and reduces the liability when payments are remitted to the applicable governmental agency or airport. Other Revenues Other revenues primarily consist of services not directly related to providing transportation, such as the advertising, marketing and brand elements of the FRONTIER Miles affinity credit card program and commissions revenue from the third-party sale of items such as rental cars and hotels. Frequent Flyer Program The Company’s FRONTIER Miles program provides frequent flyer travel awards to program members based on accumulated miles. Miles are generally accumulated as a result of travel, purchases using the co-branded credit card and purchases from other participating partners. The Company defers revenue for miles earned by passengers under its FRONTIER Miles program based on the equivalent ticket value a passenger receives by redeeming miles for a ticket rather than paying cash. The Company has a credit card affinity agreement, as amended from time to time, with its credit card partner, Barclays Bank Delaware (“Barclays”), through 2029, which provides for joint marketing, grants certain benefits to co-branded credit cardholders (“Cardholders”) and allows Barclays to market using the Company’s customer database. Cardholders earn miles under the FRONTIER Miles program and the Company sells miles at agreed-upon rates to Barclays and earns fees from Barclays for the acquisition, retention and use of the co-branded credit card by consumers. Miles are also sold to participating companies, including credit card companies and other third parties. Sales to credit card companies include multiple promised goods and services, which the Company evaluates to determine whether they represent performance obligations. The Company determined these arrangements have four separate performance obligations: (i) miles to be awarded, (ii) licensing of brand and access to member lists, (iii) advertising and marketing efforts and (iv) airline benefits. Total arrangement consideration is allocated to each performance obligation on the basis of the deliverables relative standalone selling price. For miles, the Company considers a number of entity-specific factors when developing the best estimate of the standalone selling price, including the number of miles needed to redeem an award, average fare of comparable segments, breakage and restrictions. For licensing of brand and access to member lists, the Company considers both market-specific factors and entity-specific factors, including general profit margins realized in the marketplace and industry, brand power, market royalty rates and size of customer base. For the advertising and marketing performance obligation, the Company considers market-specific factors and entity-specific factors, including the Company’s internal costs of providing services, volume of marketing efforts and overall advertising plan. For airline benefits, the Company considers the estimated opportunity cost of the award travel obligation, including elite status and other ancillary fee benefits. Consideration allocated based on the relative standalone selling price to each of the brand licensing and access to member lists, advertising and marketing elements, and airline benefits is recognized as other revenue in the Company’s consolidated statements of operations over time as services are performed. The consideration allocated to the future transportation obligations in the Company’s arrangement with Barclays is deferred and recognized as a component of passenger revenue in the Company’s consolidated statements of operations at the time of travel for miles redeemed. Miles that the Company estimates are not likely to be redeemed are subject to breakage and are recognized as a portion of passenger revenues in the Company’s consolidated statements of operations in proportion to the pattern of rights exercised by customers. Management uses statistical modeling to estimate breakage based on historical redemption patterns. A change in assumptions as to the period over which miles are expected to be redeemed, the actual redemption activity for miles or the estimated fair value of miles expected to be redeemed could have an impact on revenues in the year in which the change occurs and in future years. Redemptions are allocated between sold and flown miles based on historical patterns.
Aircraft Fuel	Aircraft fuel expense includes jet fuel and associated into-plane costs and federal and state taxes.
Sales and Marketing	Sales and marketing expense includes credit card processing fees, system booking fees and distribution costs such as the costs of the Company’s contact centers and advertising costs. Advertising and the related production costs are expensed as incurred
Income Taxes	The Company accounts for income taxes using the asset and liability method. Deferred income taxes are recognized for the tax consequences of temporary differences between the tax and financial statement reporting bases of assets and liabilities. The Company periodically assesses whether it is more likely than not that sufficient taxable income will be generated to realize deferred income tax assets, and a valuation allowance is established if it is not likely that deferred income tax assets will be realized. The Company considers sources of taxable income from prior period carryback periods, future reversals of existing taxable temporary differences, tax planning strategies and future projected taxable income when assessing the future realization of deferred tax assets. In assessing the sources of income and the need for a valuation allowance, the Company considers all available positive and negative evidence, which includes a recent history of cumulative losses.
Stock-Based Compensation	The Company recognizes cost of employee services received in exchange for awards of equity instruments based on the fair value of each instrument at the date of grant. Compensation expense is recognized over the period during which an employee is required to provide service in exchange for an award, with forfeitures accounted for as they occur. The fair value of stock option awards is estimated on the date of grant using the Black-Scholes valuation model. Restricted stock units are valued at the fair value of the shares on the date of grant. The exercise price of all stock awards is determined by the Company’s board of directors based, in part, on the ending stock price on the grant date.
Concentrations of Risk	Gulf Coast Jet and U.S. Gulf Coast indexed fuel are the Company’s basis for the majority of aircraft fuel purchases. Any disruption to the oil production or refinery capacity in the Gulf Coast or any other index, as a result of weather or any other disaster, or disruptions in the supply chain of jet fuel, dramatic escalations in the cost of jet fuel and/or the failure of fuel providers to perform under fuel arrangements for other reasons could have a material adverse effect on the Company’s financial condition and results of operations.
Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements In November 2023, the FASB issued ASU 2023-07, Segment Reporting: Improvements to Reportable Segment Disclosures, which stipulates additional segment disclosures, including new required disclosures for entities with one reportable segment. The standard is effective for annual reporting periods beginning after December 15, 2023, and interim reporting periods beginning after December 15, 2024. The standard was adopted during the year ended December 31, 2024, with updates reflected within Note 1. Recently Issued Accounting Pronouncements In December 2023, the FASB issued ASU 2023-09, Income Taxes: Improvements to Income Tax Disclosures, which requires that an entity, on an annual basis, disclose additional income tax information, primarily related to the rate reconciliation and income taxes paid. The standard is effective for annual periods beginning after December 15, 2024, with early adoption permitted. The Company is still assessing the impact of this guidance, but does not expect its adoption to have a material impact on the Company’s results of operations or financial position. In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures: Disaggregation of Income Statement Expenses, which requires additional disaggregation of certain expense categories. The standard is effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027, with early adoption permitted. The Company is still assessing the impact of this guidance, but does not expect its adoption to have a material impact on the Company’s results of operations or financial position.
Gains on Sale-Leaseback Transactions	The Company enters into sale-leaseback transactions for its aircraft and spare engine assets, whereby the Company sells one or more aircraft or aircraft engine assets to a third-party and simultaneously enters into an operating lease for a right to use such assets for a fixed period of time. Gains on sale-leaseback transactions are recognized in the period in which title to the asset transfers to the buyer-lessor and the lease commences, as a component of other operating expenses within the Company’s consolidated statements of operations. Gains on sale-leaseback transactions are calculated as the excess of the sale price of the asset over its carrying value. The carrying value of the assets sold will generally include the price paid for the asset, net of the amount of cash or the fair value of non-cash credits and incentives received from equipment and component manufacturers and any liquidated damages received from the manufacturer, the costs associated with delivery of the asset including any taxes or tariffs, financing costs capitalized in connection with the construction of the asset, capitalized maintenance and other improvements, and accumulated depreciation. Gains on sale-leaseback transactions may also be adjusted if it is determined that the terms of the sale transaction or the lease agreement are at a price other than fair value.
Fair Value Measurement	Under ASC 820, Fair Value Measurements and Disclosures, disclosures relating to how fair value is determined for assets and liabilities are required, and a hierarchy for which these assets and liabilities must be grouped is established, based on significant levels of inputs, as follows: Level 1—Quoted prices in active markets for identical assets or liabilities. Level 2—Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company utilizes several valuation techniques in order to assess the fair value of its financial assets and liabilities. Cash, Cash Equivalents and Restricted Cash Cash, cash equivalents and restricted cash are comprised of liquid money market funds, time deposits and cash, and are categorized as Level 1 instruments. The Company maintains cash with various high-quality financial institutions. See Note 1 for additional information on the Company’s restricted cash balances. Cash, cash equivalents and restricted cash are carried at cost, which management believes approximates fair value. Debt The estimated fair value of the Company’s debt agreements has been determined to be Level 3 measurement, as certain inputs used to determine the fair value of these agreements are unobservable. The Company utilizes a discounted cash flow method to estimate the fair value of the Level 3 debt.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2024

The consolidated financial statements have been prepared in accordance with the generally accepted accounting principles in the United States (“GAAP”)

Consolidation

The consolidated financial statements have been prepared in accordance with the generally accepted accounting principles in the United States (“GAAP”) and include the accounts of Frontier Group Holdings, Inc. (“FGHI” or the “Company”) and its wholly-owned direct and indirect subsidiaries, including Frontier Airlines Holdings, Inc. (“FAH”) and Frontier Airlines, Inc. (“Frontier”). All wholly-owned subsidiaries are consolidated, with all intercompany transactions and balances being eliminated.

The Company is an ultra low-cost, low-fare airline headquartered in Denver, Colorado that offers flights throughout the United States and to select international destinations in the Americas, serving approximately 100 airports.

The Company is managed as a single business unit that provides air transportation for passengers and management has concluded there is only one reportable segment. See Passenger Revenues and Other Revenues within this note for additional information on the services from which the Company derives its revenues.

The Company has identified its Chief Executive Officer and President, as its chief operating decision makers (“CODMs”). The CODMs primarily use net income to evaluate the strategic direction and assess performance of the Company. This metric is used to evaluate budget versus actual results on a regular basis and make resource allocation decisions to optimize and assess performance of the Company’s consolidated financial results. Please see the Company’s “Consolidated Statements of Operations” for net income, as well as other significant revenue and expense components of profit or loss, for the years ended December 31, 2024, 2023 and 2022. Please see the Company’s “Consolidated Balance Sheets” for total assets as of December 31, 2024 and 2023.

Reclassifications

Certain reclassifications of previously reported amounts have been made to conform to the current year presentation within the corporate tax rate reconciliation table and the net deferred tax asset (liability) table in Note 15. Income Taxes. These reclassifications did not impact previously reported amounts on the Company’s consolidated balance sheets, consolidated statements of operations, consolidated statements of comprehensive income (loss), consolidated statements of cash flows or consolidated statements of stockholders’ equity.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts in the financial statements and accompanying notes. Actual results could differ from those estimates.

Cash and Cash Equivalents and Restricted Cash

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less at the date of acquisition to be cash and cash equivalents. Additionally, any items with maturities greater than three months that are readily convertible to known amounts of cash are considered cash and cash equivalents. Investments included in this category primarily consist of money market funds and time deposits.

Restricted Cash

Restricted cash includes cash to secure medical claims paid. The Company also has covenant requirements with certain of its lenders which require cash to be deposited at the end of each quarter into a lockbox until the Company

certifies that it is in compliance with its covenants.

Accounts Receivable, net

Receivables primarily consist of amounts due from credit card receivables, amounts due from select airport locations under revenue share agreements and amounts due from Barclays as part of the Company’s credit card affinity agreement. The Company records an allowance for credit losses for amounts not expected to be collected. The Company estimates the allowance based on expected credit losses.

Supplies, net

Supplies consist of expendable aircraft spare parts, aircraft fuel and other supplies and are stated at the lower of cost or net realizable value. Supplies are accounted for on a first-in, first-out basis and are charged to expense as they are used. An allowance for obsolescence on expendable aircraft spare parts is provided over the remaining lease term or the estimated useful life of the related aircraft fleet to reduce the carrying cost of spare parts currently identified as excess to the lower of amortized cost or net realizable value.

Property and Equipment, net

Property and equipment are stated at cost and depreciated on a straight-line basis over their estimated useful lives to their estimated residual values. The Company capitalizes additions, modifications enhancing the operating performance of its assets and the interest related to payments used to acquire new aircraft and the construction of its facilities. The Company capitalizes interest attributable to pre-delivery deposit payments (“PDPs”) as an additional cost of the related asset beginning when activities necessary to get the asset ready for its intended use commence.

The Company capitalizes certain internal and external costs associated with the acquisition and development of internal-use software for new products and enhancements to existing products that have reached the application

development stage and are deemed feasible. The Company depreciates these costs using the straight-line method over the estimated useful life of the software. Capitalized costs include external direct costs of materials and services utilized in developing or obtaining internal-use software, and labor cost for employees who are directly associated with, and devote time to, internal-use software projects.

Leases

The Company leases property and equipment under operating leases. For leases with initial terms greater than 12 months, the related operating lease right-of-use asset and corresponding operating lease liability are recorded at the present value of lease payments over the term on the Company’s consolidated balance sheets. Some leases include rental escalation clauses, renewal options, termination options and/or other items that cause variability that are factored into the determination of lease payments when appropriate. The Company does not separate lease and non-lease components of contracts, except for certain flight training equipment, for which consideration is allocated between lease and non-lease components.

When available, the rate implicit in the lease is used to discount lease payments to present value; however, most leases do not provide a readily determinable implicit rate. Therefore, the Company estimates its incremental borrowing rate (“IBR”) to discount the lease payments based on information available at lease commencement. The IBR utilized by the Company is first determined using an unsecured recourse borrowing rate over a tenor that matches the period of lease payments for each individual lease and then is adjusted to arrive at a rate that is representative of a collateralized rate (secured rate). Given the Company does not have an established unsecured public credit rating, the Company utilizes current period and projected financial information to simulate an unsecured credit rating. The Company then determines its secured IBR using a combination of several valuation methods that take into account the lower amount of risk of collateralized borrowings along with observable implied credit ratings from its current outstanding secured debt obligations.

Forgivable Loans

Since 2022, the Company has launched several programs geared at attracting and retaining highly skilled pilots and mechanics. As an incentive of these programs, the Company issues forgivable loans to cadets and mechanics who join the programs, which can include pre-employment incentives such as a sign-on bonus, a monthly stipend, or reimbursement of training costs incurred. The loans and related interest are forgiven after a predetermined stay period, typically three years. Principal and interest incurred is to be repaid to the Company if a cadet or a mechanic terminates prior to the stay period being completed.

Asset Impairment

The Company applies a fair value-based impairment test to the carrying amount of indefinite-lived intangible assets annually, or more frequently if certain events or circumstances indicate impairment. The Company assesses the value of indefinite-lived assets under a qualitative and quantitative approach, as required. Under a qualitative approach, the Company considers various market factors. These factors are analyzed to determine if events and circumstances indicate that it is more likely than not that an indefinite-lived intangible asset's fair value is less than its carrying value. The quantitative approach is used to assess the asset’s fair value and the amount of the impairment. If the asset’s carrying amount exceeds its fair value calculated using the quantitative approach, an impairment charge is recorded for the difference in fair value and carrying amount. Indefinite-lived intangible assets are comprised of certain landing slot rights and the trademark of the Company.

Factors that could result in future impairment of landing slot rights, holding other assumptions constant, include, but are not limited to: (i) significant reduction in demand for air travel, (ii) competitive activity in the slotted airport, (iii) anticipated changes to the regulatory environment such as diminished slot access and (iv) increased competition at a nearby airport. As part of this evaluation, the Company assesses whether changes in (i) macroeconomic conditions, (ii) industry and market conditions, (iii) cost factors, (iv) overall financial performance and (v) certain events specific to the Company, have occurred which would impact the use and/or fair value of these assets.

Based on the Company’s qualitative analysis performed during the fourth quarter of 2024, the Company concluded it is more likely than not that the fair values of its indefinite-lived intangible assets are greater than the carrying amount. Therefore, a quantitative assessment was not necessary. No impairments have been recorded in any periods presented. Finite-lived intangible assets are comprised of the Company’s affinity credit card program relationship recognized in connection with acquisition accounting and are amortized over their estimated economic useful life.

The Company records impairment charges on long-lived assets used in operations and finite-lived intangible assets when events and circumstances indicate that the assets may be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets, and the net book value of the assets exceeds their estimated fair value. In making these determinations, the Company uses certain assumptions, including, but not limited to: (i) estimated fair value of the assets; and (ii) estimated undiscounted future cash flows expected to be generated by these assets, which are based on additional assumptions such as asset utilization including macroeconomic factors impacting future demand, length of service the asset will be used in the Company’s operations and estimated salvage values.

Aircraft Maintenance

The Company accounts for heavy maintenance and major overhauls under the deferral method, whereby the cost of heavy maintenance and major overhauls is deferred and recorded as flight equipment and depreciated over the lesser of the remaining lease term or the period until the next scheduled heavy maintenance event. The Company has separate maintenance cost-per-hour contracts for the repair of certain rotable parts to support airframe and engine maintenance and repair. These agreements require monthly payments based upon utilization, such as flight hours, cycles and age of the aircraft. For the contracts in which risk has been determined to transfer to the service provider, expense is recognized based on the contractual terms of the cost-per-hour arrangement. For those contracts in which risk has not been determined to transfer to the service provider, the Company initially records monthly payments as a deposit included in other assets on the Company’s consolidated balance sheets and then accounts for the underlying maintenance event when it occurs, in accordance with the Company’s maintenance accounting policy.

Previously, certain of the Company’s aircraft lease agreements required, and may again require in the future, the Company to pay maintenance reserves to aircraft lessors to be held as collateral in advance of the Company’s

required performance of major maintenance activities. At lease inception and at each balance sheet date, the Company assesses whether the maintenance reserve payments required by its leases are substantively and contractually related to the maintenance of the leased asset. Maintenance reserve payments that are determined to be related to the maintenance of the leased asset are accounted for as maintenance deposits, to the extent they are expected to be recoverable, and are reflected as aircraft maintenance deposits on the Company’s consolidated balance sheets. As the eligible maintenance is performed, the maintenance deposits are recorded in accounts receivable, net on the Company’s consolidated balance sheets. When it is not probable that the Company will recover amounts on deposit with a lessor, such amounts are expensed as supplemental rent within aircraft rent in the Company’s consolidated statements of operations. Maintenance reserve payments that are based on a utilization measure and are not probable of being recovered are considered variable lease payments and are not included within the right-of-use asset and respective lease liability. During the year ended December 31, 2024, an agreement was reached with one of the Company’s aircraft lessors which eliminated requirement to pay maintenance reserves held as collateral in advance of the Company’s required performance of major maintenance activities on its aircraft leases. As a result, none of the Company’s current aircraft lessors require these payments to be held as collateral.

When the Company is required to pay maintenance reserves to aircraft lessors, the Company makes certain assumptions at the inception of the lease and at each balance sheet date to determine the recoverability of maintenance deposits. These assumptions are based on various factors, such as the estimated time between the maintenance events, the cost of such maintenance events, the date the aircraft is due to be returned to the lessor and the number of flight hours and cycles the aircraft is estimated to be utilized before it is returned to the lessor. Changes in estimates are accounted for on a cumulative catch-up basis. On a regular basis, the Company assesses the credit worthiness of the Company’s lessors to ensure deposits are collectible and, specifically, whether any credit losses exist for aircraft maintenance deposits. Based on these assessments, the Company determined no allowance was necessary as of December 31, 2024 and 2023.

Certain of the Company’s historical lease agreements have provided, and future lease agreements may provide, that maintenance reserves held by the lessor at the expiration of the lease are nonrefundable to the Company and will be retained by the lessor. Consequently, any usage-based maintenance reserve payments after the last major maintenance event would not substantively be related to the maintenance of the leased asset and, therefore, would be accounted for as supplemental rent.

Leased Aircraft Return Costs

The Company’s aircraft lease agreements generally contain provisions that require the Company to return aircraft airframes and engines to the lessor in a specified condition or pay an amount to the lessor based on the airframe and engine’s actual return condition. Lease return costs include all costs that would be incurred at the return of the aircraft, including costs incurred to repair the airframe and engines to the condition required by the lease.

Lease return costs could include, but are not limited to, redelivery cost, redelivery crew cost, fuel, final inspections, reconfiguration of the cabin, repairs to the airframe, painting, overhaul of engines, replacement of components and checks. These return provisions are evaluated at inception of the lease and throughout the lease terms and are accounted for as either fixed or variable lease payments (depending on the nature of the lease return condition) when it is probable that such amounts will be incurred. When determining probability and estimated cost, there are various other factors which need to be considered such as current condition of the aircraft, the age of the aircraft at lease expiration, number of hours run on the engines, number of cycles run on the airframe, projected number of hours run on the engine at the time of return, the projected number of cycles run on the airframe at the time of return, the extent of repairs needed, if any, upon return, return locations, current configuration of the aircraft, current paint of the aircraft, estimated escalation of cost of repairs and materials at the time of return, current flight hour agreement rates and future flight hour agreement rates. In addition, typically near the lease return date, the lessors may allow maintenance reserves to be applied as return condition consideration or pass on certain return provisions if they do not align with their current plans to remarket the aircraft. As a result of the different factors listed above, management assesses the need to accrue lease return costs throughout the lease as facts and

circumstances warrant an assessment. When costs become both probable and estimable, lease return costs are expensed as a component of aircraft rent in the Company’s consolidated statements of operations through the remaining lease term.

Derivative Instruments

The Company is party to certain interest rate swaption agreements that are accounted for as cash flow hedges, as defined under ASC 815, Derivatives and Hedging. Some of the Company’s aircraft and spare engine sale-leaseback agreements can expose it to interest rate risk as, depending on the agreement, rental payments are adjusted and become fixed based on the swap rate at the time of delivery. The primary objective for interest rate derivatives is to hedge the portion of the estimated future monthly rental payments related to the associated agreement’s variable interest rate, primarily the Secured Overnight Financing Rate (“SOFR”). These swaption agreements provide for a single payment at maturity based upon the change in the applicable swap rate between the execution date and the termination date. For interest rate derivatives, the Company recognizes the associated gains or losses deferred in accumulated other comprehensive income/(loss) (“AOCI/L”), as well as amounts that are paid or received in connection with the purchase or sale of interest rate derivative instruments (i.e., premium costs of swaption contracts), as a component of aircraft rent expense within the Company’s consolidated statements of operations over the period of the related aircraft lease. Cash flows related to interest rate swaption agreements are classified as operating activities in the Company’s consolidated statements of cash flows. The Company presents its interest rate swaption derivative instruments gross on the consolidated balance sheets. The Company does not enter into derivative instruments for speculative purposes.

Revenue

Fare revenues. Tickets sold in advance of the flight date are initially recorded as an air traffic liability on the Company’s consolidated balance sheets. Fare revenues are generally recognized in passenger revenues within the Company’s consolidated statements of operations at the time of departure when transportation is provided.

Non-fare passenger revenues. Certain ancillary items such as service fees, baggage and seat selection deemed part of providing passenger transportation are recognized to non-fare passenger revenues in passenger revenues within the Company’s consolidated statements of operations at the time of departure. Service fees include, among other things, convenience fees, charges for nonrefundable ticket expiration, cancellation charges and service charges assessed for itinerary changes made prior to the date of departure. Such change fees are recognized at the time of departure of the newly scheduled travel.

Passenger Taxes and Fees. The Company is required to collect certain taxes and fees from customers on behalf of government agencies and airports and remit these back to the applicable governmental entity or airport on a periodic basis. These taxes and fees include U.S. federal transportation taxes, federal security charges, airport passenger facility charges, and foreign arrival and departure taxes. These taxes and fees are collected from customers at the time they purchase their tickets but are not included in passenger revenues. The Company records a liability within other current liabilities on the consolidated balance sheets upon collection from the customer, and reduces the liability when payments are remitted to the applicable governmental agency or airport.

Other Revenues

Other revenues primarily consist of services not directly related to providing transportation, such as the advertising, marketing and brand elements of the FRONTIER Miles affinity credit card program and commissions revenue from the third-party sale of items such as rental cars and hotels.

Frequent Flyer Program

The Company’s FRONTIER Miles program provides frequent flyer travel awards to program members based on accumulated miles. Miles are generally accumulated as a result of travel, purchases using the co-branded credit card and purchases from other participating partners. The Company defers revenue for miles earned by passengers under its FRONTIER Miles program based on the equivalent ticket value a passenger receives by redeeming miles for a ticket rather than paying cash.

The Company has a credit card affinity agreement, as amended from time to time, with its credit card partner, Barclays Bank Delaware (“Barclays”), through 2029, which provides for joint marketing, grants certain benefits to co-branded credit cardholders (“Cardholders”) and allows Barclays to market using the Company’s customer database. Cardholders earn miles under the FRONTIER Miles program and the Company sells miles at agreed-upon rates to Barclays and earns fees from Barclays for the acquisition, retention and use of the co-branded credit card by consumers.

Miles are also sold to participating companies, including credit card companies and other third parties. Sales to credit card companies include multiple promised goods and services, which the Company evaluates to determine whether they represent performance obligations. The Company determined these arrangements have four separate performance obligations: (i) miles to be awarded, (ii) licensing of brand and access to member lists, (iii) advertising and marketing efforts and (iv) airline benefits. Total arrangement consideration is allocated to each performance obligation on the basis of the deliverables relative standalone selling price. For miles, the Company considers a number of entity-specific factors when developing the best estimate of the standalone selling price, including the number of miles needed to redeem an award, average fare of comparable segments, breakage and restrictions. For licensing of brand and access to member lists, the Company considers both market-specific factors and entity-specific factors, including general profit margins realized in the marketplace and industry, brand power, market royalty rates and size of customer base. For the advertising and marketing performance obligation, the Company considers market-specific factors and entity-specific factors, including the Company’s internal costs of providing services, volume of marketing efforts and overall advertising plan. For airline benefits, the Company considers the estimated opportunity cost of the award travel obligation, including elite status and other ancillary fee benefits.

Consideration allocated based on the relative standalone selling price to each of the brand licensing and access to member lists, advertising and marketing elements, and airline benefits is recognized as other revenue in the Company’s consolidated statements of operations over time as services are performed. The consideration allocated to the future transportation obligations in the Company’s arrangement with Barclays is deferred and recognized as a component of passenger revenue in the Company’s consolidated statements of operations at the time of travel for miles redeemed. Miles that the Company estimates are not likely to be redeemed are subject to breakage and are recognized as a portion of passenger revenues in the Company’s consolidated statements of operations in proportion to the pattern of rights exercised by customers. Management uses statistical modeling to estimate breakage based on historical redemption patterns. A change in assumptions as to the period over which miles are expected to be redeemed, the actual redemption activity for miles or the estimated fair value of miles expected to be redeemed could have an impact on revenues in the year in which the change occurs and in future years. Redemptions are allocated between sold and flown miles based on historical patterns.

Aircraft Fuel

Aircraft fuel expense includes jet fuel and associated into-plane costs and federal and state taxes.

Sales and Marketing

Sales and marketing expense includes credit card processing fees, system booking fees and distribution costs such as the costs of the Company’s contact centers and advertising costs. Advertising and the related production costs are expensed as incurred

Income Taxes

The Company accounts for income taxes using the asset and liability method. Deferred income taxes are recognized for the tax consequences of temporary differences between the tax and financial statement reporting bases of assets and liabilities. The Company periodically assesses whether it is more likely than not that sufficient taxable income will be generated to realize deferred income tax assets, and a valuation allowance is established if it is not likely that deferred income tax assets will be realized. The Company considers sources of taxable income from prior period carryback periods, future reversals of existing taxable temporary differences, tax planning strategies and future projected taxable income when assessing the future realization of deferred tax assets. In assessing the sources of income and the need for a valuation allowance, the Company considers all available positive and negative evidence, which includes a recent history of cumulative losses.

Stock-Based Compensation

The Company recognizes cost of employee services received in exchange for awards of equity instruments based on the fair value of each instrument at the date of grant. Compensation expense is recognized over the period during which an employee is required to provide service in exchange for an award, with forfeitures accounted for as they occur. The fair value of stock option awards is estimated on the date of grant using the Black-Scholes valuation model. Restricted stock units are valued at the fair value of the shares on the date of grant. The exercise price of all stock awards is determined by the Company’s board of directors based, in part, on the ending stock price on the grant date.

Concentrations of Risk

Gulf Coast Jet and U.S. Gulf Coast indexed fuel are the Company’s basis for the majority of aircraft fuel purchases. Any disruption to the oil production or refinery capacity in the Gulf Coast or any other index, as a result of weather or any other disaster, or disruptions in the supply chain of jet fuel, dramatic escalations in the cost of jet fuel and/or the failure of fuel providers to perform under fuel arrangements for other reasons could have a material adverse effect on the Company’s financial condition and results of operations.

Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements

Recently Adopted Accounting Pronouncements

In November 2023, the FASB issued ASU 2023-07, Segment Reporting: Improvements to Reportable Segment Disclosures, which stipulates additional segment disclosures, including new required disclosures for entities with one reportable segment. The standard is effective for annual reporting periods beginning after December 15, 2023, and interim reporting periods beginning after December 15, 2024. The standard was adopted during the year ended December 31, 2024, with updates reflected within Note 1.

Recently Issued Accounting Pronouncements

In December 2023, the FASB issued ASU 2023-09, Income Taxes: Improvements to Income Tax Disclosures, which requires that an entity, on an annual basis, disclose additional income tax information, primarily related to the rate reconciliation and income taxes paid. The standard is effective for annual periods beginning after December 15, 2024, with early adoption permitted. The Company is still assessing the impact of this guidance, but does not expect its adoption to have a material impact on the Company’s results of operations or financial position.

In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures: Disaggregation of Income Statement Expenses, which requires additional disaggregation of certain expense categories. The standard is effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027, with early adoption permitted. The Company is still assessing the impact of this guidance, but does not expect its adoption to have a material impact on the Company’s results of operations or financial position.

Gains on Sale-Leaseback Transactions

The Company enters into sale-leaseback transactions for its aircraft and spare engine assets, whereby the Company sells one or more aircraft or aircraft engine assets to a third-party and simultaneously enters into an operating lease for a right to use such assets for a fixed period of time. Gains on sale-leaseback transactions are recognized in the period in which title to the asset transfers to the buyer-lessor and the lease commences, as a component of other operating expenses within the Company’s consolidated statements of operations. Gains on sale-leaseback transactions are calculated as the excess of the sale price of the asset over its carrying value. The carrying value of the assets sold will generally include the price paid for the asset, net of the amount of cash or the fair value of non-cash credits and incentives received from equipment and component manufacturers and any liquidated damages received from the manufacturer, the costs associated with delivery of the asset including any taxes or tariffs, financing costs capitalized in connection with the construction of the asset, capitalized maintenance and other improvements, and accumulated depreciation. Gains on sale-leaseback transactions may also be adjusted if it is determined that the terms of the sale transaction or the lease agreement are at a price other than fair value.

Fair Value Measurement

Under ASC 820, Fair Value Measurements and Disclosures, disclosures relating to how fair value is determined for assets and liabilities are required, and a hierarchy for which these assets and liabilities must be grouped is established, based on significant levels of inputs, as follows:

Level 1—Quoted prices in active markets for identical assets or liabilities.

Level 2—Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company utilizes several valuation techniques in order to assess the fair value of its financial assets and liabilities.

Cash, Cash Equivalents and Restricted Cash

Cash, cash equivalents and restricted cash are comprised of liquid money market funds, time deposits and cash, and are categorized as Level 1 instruments. The Company maintains cash with various high-quality financial institutions. See Note 1 for additional information on the Company’s restricted cash balances. Cash, cash equivalents and restricted cash are carried at cost, which management believes approximates fair value.

Debt

The estimated fair value of the Company’s debt agreements has been determined to be Level 3 measurement, as certain inputs used to determine the fair value of these agreements are unobservable. The Company utilizes a discounted cash flow method to estimate the fair value of the Level 3 debt.