Ticket revenue is recorded as Passenger revenue, and represents the primary source of the Company's revenue. Also included in Passenger revenue are passenger ancillary revenues such as bag fees, on-board food and beverage, ticket change fees, and certain revenue from the frequent flyer program. In 2020, the Company eliminated ticket change fees indefinitely from main cabin and first class fares. Mileage Plan other revenue includes brand and marketing revenue from our co-branded credit card and other partners and certain interline frequent flyer revenue, net of commissions. Cargo and other revenue includes freight and mail revenue, and to a lesser extent, other ancillary revenue products such as lounge membership and certain commissions.

The Company disaggregates revenue by segment in Note 13. The level of detail within the Company’s consolidated statements of operations, segment disclosures, and in this footnote depict the nature, amount, timing and uncertainty of revenue and how cash flows are affected by economic and other factors.

The primary performance obligation on a typical passenger ticket is to provide air travel to the passenger. Ticket revenue is collected in advance of travel and recorded as ATL on the consolidated balance sheets. The Company satisfies its performance obligation and recognizes ticket revenue for each flight segment when the transportation is provided.

Ancillary passenger revenues relate to items such as checked-bag fees, ticket change fees (prior to 2021), and on-board food and beverage sales, all of which are provided at time of flight. As such, the obligation to perform these services is satisfied at the time of travel and is recorded with ticket revenue in Passenger revenue.

Revenue is also recognized for tickets that are expected to expire unused, a concept referred to as “passenger ticket breakage.” Passenger ticket breakage is recorded at the intended travel date using estimates made at the time of sale based on the Company’s historical experience of expired tickets, and other facts such as program changes and modifications. Differences between advance passenger ticket breakage estimates and actual expirations are recognized as revenue when changes to estimate assumptions are observed or when tickets are no longer valid.

In addition to selling tickets on its own marketed flights, Alaska has interline agreements with partner airlines under which it sells multi-city tickets with one or more segments of the trip flown by a partner airline, or it operates a connecting flight sold by a partner airline. Each segment in a connecting flight represents a separate performance obligation. Revenue on segments sold and operated by the Company is recognized as Passenger revenue in the gross amount of the allocated ticket price when the travel occurs, while the commission paid to the partner airline is recognized as a selling expense when the related transportation is provided. Revenue on segments operated by a partner airline is deferred for the full amount of the consideration received at the time the ticket is sold and, once the segment has been flown the Company records the net amount, after compensating the partner airline, as Cargo and other revenue.

A portion of revenue from the Mileage Plan program is recorded in Passenger revenue. As members are awarded mileage credits on flown tickets, these credits become a distinct performance obligation to the Company. The Company allocates the transaction price to each performance obligation identified in a passenger ticket contract on a relative standalone selling price basis. The standalone selling price for loyalty mileage credits issued is discussed in the Loyalty Mileage Credits section of this Note below. The amount allocated to the mileage credits is deferred on the balance sheet. Once a member travels using a travel award redeemed with mileage credits on one of the Company's airline carriers, the revenue associated with those mileage credits is recorded as Passenger revenue.

Passenger revenue recognized in the consolidated statements of operations (in millions):


	Twelve Months Ended December 31,
	2021		2020		2019
Passenger ticket revenue, including ticket breakage and net of taxes and fees	$	4,533	$	2,428	$	6,824
Passenger ancillary revenue	327		245		567
Mileage Plan passenger revenue	639		346		704
Total Passenger revenue	$	5,499	$	3,019	$	8,095

As passenger tickets and related ancillary services are primarily sold via credit cards, certain amounts due from credit card processors are recorded as airline traffic receivables. These credit card receivables and receivables from our affinity credit card partner represent $167 million and $83 million on the consolidated balance sheets as of December 31, 2021 and 2020.

For performance obligations with performance periods of less than one year, GAAP provides a practical expedient that allows the Company not to disclose the transaction price allocated to remaining performance obligations and the timing of related revenue recognition. As passenger tickets expire one year from ticketing, if unused or not exchanged, the Company elected to apply this practical expedient.

The Company’s Mileage Plan loyalty program provides frequent flyer travel awards to program members based upon accumulated loyalty mileage credits. Mileage credits are earned through travel, purchases using the Mileage Plan co-branded credit card and purchases from other participating partners. The program has a 24-month expiration period for unused mileage credits from the month of last account activity. In response to the COVID-19 pandemic, the Company suspended expiry of outstanding mileage credits through June 30, 2022. The Company offers redemption of mileage credits through free, discounted or upgraded air travel on flights operated by Alaska and its regional partners or on one of its 23 partners, as well as redemption at partner hotels.

The Company uses a relative standalone selling price to allocate consideration to material performance obligations in contracts with customers that include loyalty mileage credits. As directly observable selling prices for mileage credits are not available, the Company determines the standalone selling price of mileage credits primarily using actual ticket purchase prices for similar tickets flown, adjusted for the likelihood of redemption, or breakage. In determining similar tickets flown, the Company considers current market prices, class of service, type of award, and other factors. For mileage credits accumulated through travel on partner airlines, the Company uses actual consideration received from the partners.

Revenue related to air transportation is deferred in the amount of the relative standalone selling price allocated to the loyalty mileage credits as they are issued. The Company satisfies its performance obligation when the mileage credits are redeemed and the related air transportation is delivered.

The Company estimates breakage for the portion of loyalty mileage credits not expected to be redeemed using a statistical analysis of historical data, including actual mileage credits expiring, slow-moving and low-credit accounts, among other factors. The breakage rate for the twelve months ended December 31, 2021 and 2020 was 17.4%. The Company reviews the breakage rate used on an annual basis.

In addition to mileage credits, the co-brand credit card agreements, referred to herein as the Agreements, also include performance obligations for waived bag fees, Companion Fare™ offers to purchase an additional ticket at a discount, marketing, and the use of intellectual property including the brand (unlimited access to the use of the Company’s brand and frequent flyer member lists), which is the predominant element in the Agreement. The co-brand card bank partners are the customer for some elements, including the brand and marketing, while the Mileage Plan member is the customer for other elements such as mileage credits, bag waivers, and companion fares.

At the inception of the Agreement, management estimated the selling price of each of the performance obligations. The objective was to determine the price at which a sale would be transacted if the product or service was sold on a stand-alone basis. The Company determined its best estimate of selling price for each element by considering multiple inputs and methods including, but not limited to, the estimated selling price of comparable travel, discounted cash flows, brand value, published selling prices, number of miles awarded, and number of miles redeemed. The Company estimated the selling prices and volumes over the term of the Agreement in order to determine the allocation of proceeds to each of the multiple deliverables. The estimates of the standalone selling prices of each element do not change subsequent to the original valuation of the contract unless the contract is materially modified, but the allocation between elements may change based upon the actual and updated projected volumes of each element delivered during the term of the contract.

Consideration received from the banks is variable and is primarily from consumer spend on the card, among other items. The Company allocates consideration to each of the performance obligations, including mileage credits, waived bag fees, companion fares, and brand and marketing, using their relative standalone selling price. Because the performance obligation related to providing use of intellectual property including the brand is satisfied over time, it is recognized in Mileage Plan other revenue in the period that those elements are sold. The Company records passenger revenue related to the air transportation and certificates for discounted companion travel when the transportation is delivered.

In contracts with non-bank partners, the Company has identified two performance obligations in most cases - travel and brand. The travel performance obligation is deferred until the transportation is provided in the amount of the estimated standalone selling price of the ticket, less breakage, and the brand performance obligation is recognized using the residual method as commission revenue when the brand element is sold. Mileage credit sales recorded under the residual approach are immaterial to the overall program.

Alaska has interline arrangements with certain airlines whereby its members may earn and redeem Mileage Plan credits on those airlines, and members of a partner airline’s loyalty program may earn and redeem frequent flyer program credits on flights operated by Alaska and its regional partners. When a Mileage Plan member earns credits on a partner airline, the partner airline remits a contractually-agreed upon fee to the Company which is deferred until credits are redeemed. When a Mileage Plan member redeems credits on a partner airline, the Company pays a contractually agreed upon fee to the other airline, which is netted against the revenue recognized associated with the award travel. When a member of a partner airline redeems frequent flyer credits on Alaska, the partner airline remits a contractually-agreed upon amount to the Company, recognized as Passenger revenue upon travel. If the partner airline’s member earns frequent flyer program credits on an Alaska flight, the Company remits a contractually-agreed upon fee to the partner airline and records a commission expense.

Mileage Plan revenue included in the consolidated statements of operations (in millions):


	Twelve Months Ended December 31,
	2021		2020		2019
Passenger revenue	$	639	$	346	$	704
Mileage Plan other revenue	461		374		465
Total Mileage Plan revenue	$	1,100	$	720	$	1,169

The Company provides freight and mail services (cargo). The majority of cargo services are provided to commercial businesses and the United States Postal Service. The Company satisfies cargo service performance obligations and recognizes revenue when the shipment arrives at its final destination, or is transferred to a third-party carrier for delivery.

The Company also earns other revenue for lounge memberships, hotel and car commissions, and certain other immaterial items not intrinsically tied to providing air travel to passengers. Revenue is recognized when these services are rendered and recorded as Cargo and other revenue. The transaction price for Cargo and other revenue is the price paid by the customer.

Cargo and other revenue included in the consolidated statements of operations (in millions):


	Twelve Months Ended December 31,
	2021		2020		2019
Cargo revenue	$	124	$	112	$	133
Other revenue	92		61		88
Total Cargo and other revenue	$	216	$	173	$	221

Included within the air traffic liability on the consolidated balance sheets is an outstanding liability for travel credits that guests may utilize for future travel. A high volume of credits were issued in 2020 as a result of the COVID-19 pandemic, and issuance levels in 2021 normalized, though remain above pre-pandemic levels. In April 2021, as part of the Company's COVID-19 relief measures, travel credits that were set to expire at any point in 2021 were extended through December 31, 2021 for possible travel through November 30, 2022. Of these credits, those not redeemed for travel by December 31, 2021 expired and were recognized as revenue in 2021.

The total deferred revenue liability included on the consolidated balance sheets represents the remaining transaction price that has been allocated to Mileage Plan performance obligations not yet satisfied by the Company. In general, the current amounts will be recognized as revenue within 12 months and the long-term amounts will be recognized as revenue over a period of approximately three to four years. This period of time represents the average time that members have historically taken to earn and redeem miles.

The Company records a receivable for amounts due from the affinity card partner and from other partners as mileage credits are sold until the payments are collected. The Company had $62 million and $48 million of such receivables as of December 31, 2021 and December 31, 2020.

Mileage credits are combined into one homogeneous pool and are not specifically identifiable. As such, loyalty revenues disclosed earlier in this Note are comprised of miles that were part of the deferred revenue and liabilities balances at the beginning of the period and miles that were issued during the period. The table below presents a roll forward of the total frequent flyer liability (in millions):


	Twelve Months Ended December 31,
	2021		2020
Total Deferred Revenue balance at January 1	$	2,277	$	1,990
Travel miles and companion certificate redemption - Passenger revenue	(639)		(346)
Miles redeemed on partner airlines - Other revenue	(43)		(23)
Increase in liability for mileage credits issued	763		656
Total Deferred Revenue balance at December 31	$	2,358	$	2,277

Certain costs such as credit card fees, travel agency and other commissions paid, as well as Global Distribution Systems booking fees, are incurred when the Company sells passenger tickets and ancillary services in advance of the travel date. The Company defers such costs and recognizes them as expenses when the travel occurs. Prepaid expense recorded on the consolidated balance sheets for such costs was $37 million and $24 million as of December 31, 2021 and December 31, 2020. The Company recorded related expense on the consolidated statements of operations of $90 million, $43 million and $208 million for the twelve months ended December 31, 2021, 2020 and 2019.