Revenue Recognition

Passenger revenues

Fare revenues. Tickets sold are initially deferred as “air traffic liability.” Passenger fare revenues are recognized at time of departure when transportation is provided. All tickets sold by the Company are nonrefundable. An unused ticket expires at the date of scheduled travel and is recognized as revenue at the date of scheduled travel. Passenger revenues reported prior to the adoption of ASU 2014-09 are now reported as fare revenues within passenger revenues in the Company's disaggregated revenue table within Note 4, Revenue Disaggregation.

As of December 31, 2017 and 2016, the Company had air traffic liability ("ATL") balances of $263.7 million and $220.2 million, respectively. During the six months ended June 30, 2018, substantially all of the ATL balance as of December 31, 2017 has been recognized. The remaining balance of the December 31, 2017 liability is expected to be recognized during the remainder of 2018.

Non-fare revenues.The adoption of ASU 2014-09 impacted the classification of certain ancillary items such as bags, seats and other travel-related fees, since they are deemed part of the single performance obligation of providing passenger transportation. These ancillary items are now recognized in non-fare revenues within passenger revenues in the Company's disaggregated revenue table within Note 4, Revenue Disaggregation.

Changes and cancellations. Customers may elect to change or cancel their itinerary prior to the date of departure. For changes, a service charge is recognized at time of departure of newly scheduled travel and is deducted from the face value of the original purchase price of the ticket, and the original ticket becomes invalid. For cancellations, a service charge is assessed and the amount remaining after deducting the service charge is called a credit shell which generally expires 60 days from the date the credit shell is created and can be used towards the purchase of a new ticket and the Company’s other service offerings. Both the service charge and credit shell amounts are recorded as deferred revenue and amounts expected to expire are estimated based on historical experience. Estimating the amount of credits that will go unused involves some level of subjectivity and judgment. However, given the relatively short period of time to expiration, this does not have a significant impact on the Company's financial statements.

Other revenues

Other revenues primarily consist of the marketing component of the sale of frequent flyer miles to the Company's credit card partner and commissions revenue from the sale of various items such as hotels and rental cars.

Frequent Flyer Program

The Company's frequent flyer program generates customer loyalty by rewarding customers with mileage credits to travel on Spirit. When traveling, customers earn redeemable mileage credits for each mile flown on Spirit. Customers can also earn mileage credits through participating companies such as the co-branded Spirit credit card. Mileage credits are redeemable by customers in future periods for air travel on Spirit.

To reflect the mileage credits earned, the program includes two types of transactions that are considered revenue arrangements with multiple performance obligations: (1) mileage credits earned with travel and (2) mileage credits sold to co-branded credit card partner.

The adoption of ASU 2014-09 eliminated the incremental cost method for frequent flier program accounting, which required the Company to re-value and record a liability associated with customer flight miles earned with travel as part of the Company’s frequent flier program with a relative fair value. Upon adoption of ASU 2014-09 on January 1, 2018, the Company recorded an increase to its air traffic liability of $12.4 million.

Passenger ticket sales earning mileage credits. Passenger ticket sales earning mileage credits provide customers with (1) mileage credits earned and (2) air transportation. The Company values each performance obligation on a standalone basis. To value the mileage credits earned, the Company considers the quantitative value a passenger receives by redeeming miles for a ticket rather than paying cash, which is referred to as equivalent ticket value ("ETV").

The Company defers revenue for the mileage credits when earned and recognize loyalty travel awards in passenger revenue as the miles are redeemed and services are provided. The Company records the air transportation portion of the passenger ticket sales in air traffic liability and recognizes passenger revenue when transportation is provided or if the ticket goes unused.

Sale of mileage credits. Customers may earn mileage credits based on their spending with the Company's co-branded credit card company with which the Company has an agreement to sell mileage credits. The contract to sell mileage credits under this agreement has multiple performance obligations. During the six months ended June 30, 2018 and 2017, total cash sales from this agreement was $19.9 million and $25.0 million, respectively, which are allocated to travel and other performance obligations, as discussed below.

The Company's co-brand credit card agreement provides for joint marketing where cardholders earn mileage credits for making purchases using co-branded cards. During 2015, the Company extended its agreement with the administer of the FREE SPIRIT affinity credit card program to extend through 2022. The Company accounts for this agreement consistently with the accounting method that allocates the consideration received to the individual products and services delivered. The value is allocated based on the relative selling prices of those products and services, which generally consists of (i) travel miles to be awarded, (ii) licensing of brand and access to member lists and (iii) advertising and marketing efforts. The Company determined the best estimate of the selling prices by considering discounted cash flow analysis using multiple inputs and assumptions, including: (1) the expected number of miles awarded and number of miles redeemed, (2) ETV for the award travel obligation, (3) licensing of brand and access to member lists and (4) advertising and marketing efforts.

The Company defers the amount for award travel obligation as part of loyalty deferred revenue within air traffic liability on the balance sheet and recognizes loyalty travel awards in passenger revenue as the mileage credits are used for travel. Revenue allocated to the remaining performance obligations, primarily marketing components, is recorded in other revenue over time as miles are delivered.

Mileage breakage. For mileage credits that the Company estimates are not likely to be redeemed ("breakage"), the Company recognizes the associated value proportionally during the period in which the remaining mileage credits are redeemed. Management uses statistical models to estimate breakage based on historical redemption patterns. A change in assumptions as to the period over which mileage credits are expected to be redeemed, the actual redemption activity for mileage credits or the estimated fair value of mileage credits expected to be redeemed could have an impact on revenues in the year in which the change occurs and in future years.

Current activity of frequent flyer program. Mileage credits are combined in one homogeneous pool and are not separately identifiable. As such, the revenue is comprised of miles that were part of the frequent flyer deferred revenue balance at the beginning of the period as well as miles that were issued during the period.

The following tables show adjustments made due to the adoption of ASU 2014-09 on the December 31, 2017 and 2016 statements of operations. Previously reported results were derived from audited financial statements included in Company's Annual Report on Form 10-K for the fiscal years ended December 31, 2017 and December 31, 2016, as applicable.



	Year Ended December 31, 2017
	(in thousands, except share and per share data)
	As Reported			Topic 606 Adjustment			As Adjusted
Operating revenues:
Passenger	$	1,366,034		$	1,206,853		$	2,572,887
Other	1,281,632			(1,210,967		)	70,665
Total operating revenues	2,647,666			(4,114		)	2,643,552

Operating expenses:
Aircraft fuel	615,581			—			615,581
Salaries, wages and benefits	527,959			—			527,959
Aircraft rent	205,852			—			205,852
Landing fees and other rents	180,655			—			180,655
Depreciation and amortization	140,152			—			140,152
Maintenance, materials and repairs	110,439			—			110,439
Distribution	113,620			(148		)	113,472
Special charges	12,629			—			12,629
Loss on disposal of assets	4,168			—			4,168
Other operating	347,820			—			347,820
Total operating expenses	2,258,875			(148		)	2,258,727

Operating income	388,791			(3,966		)	384,825

Other (income) expense:
Interest expense	57,302			—			57,302
Capitalized interest	(13,793		)	—			(13,793		)
Interest income	(8,736		)	—			(8,736		)
Other expense	366			—			366
Total other (income) expense	35,139			—			35,139

Income before income taxes	353,652			(3,966		)	349,686
Provision (benefit) for income taxes	(66,954		)	1,118			(65,836		)

Net income	$	420,606		$	(5,084	)	$	415,522
Basic earnings per share	$	6.08		$	(0.07	)	$	6.00
Diluted earnings per share	$	6.06		$	(0.07	)	$	5.99



	Year Ended December 31, 2016
	(in thousands, except share and per share data)
	As Reported			Topic 606 Adjustment			As Adjusted
Operating revenues:
Passenger	$	1,200,621		$	1,057,180		$	2,257,801
Other	1,121,335			(1,059,115		)	62,220
Total operating revenues	2,321,956			(1,935		)	2,320,021

Operating expenses:
Salaries, wages and benefits	472,471			—			472,471
Aircraft fuel	447,553			—			447,553
Aircraft rent	201,675			—			201,675
Landing fees and other rents	151,679			—			151,679
Depreciation and amortization	101,136			—			101,136
Maintenance, materials and repairs	98,587			—			98,587
Distribution	96,627			268			96,895
Special charges	37,189			—			37,189
Loss on disposal of assets	4,187			—			4,187
Other operating	267,191			—			267,191
Total operating expenses	1,878,295			268			1,878,563

Operating income	443,661			(2,203		)	441,458

Other (income) expense:
Interest expense	41,654			—			41,654
Capitalized interest	(12,705		)	—			(12,705		)
Interest income	(5,276		)	—			(5,276		)
Other expense	528			—			528
Total other (income) expense	24,201			—			24,201

Income before income taxes	419,460			(2,203		)	417,257
Provision (benefit) for income taxes	154,581			(807		)	153,774

Net income	$	264,879		$	(1,396	)	$	263,483
Basic earnings per share	$	3.77		$	(0.02	)	$	3.75
Diluted earnings per share	$	3.76		$	(0.02	)	$	3.74

The following table shows adjusted balances after the adoption of ASU 2014-09 on the quarterly statements of operations for each quarter of 2017.



	For the Quarter Ended
	March 31, 2017			June 30, 2017			September 30, 2017			December 31, 2017
	(in thousands, except share and per share data)
Operating revenues:
Passenger	$	572,287		$	680,880		$	669,072		$	650,647
Other	17,670			19,305			18,155			15,535
Total operating revenues	589,957			700,185			687,227			666,182

Operating expenses:
Aircraft fuel	139,782			142,294			158,300			175,205
Salaries, wages and benefits	127,138			129,892			134,114			136,815
Aircraft rent	57,070			52,566			53,396			42,820
Landing fees and other rents	40,448			45,592			48,498			46,117
Depreciation and amortization	31,509			35,331			36,840			36,472
Maintenance, materials and repairs	26,312			28,985			26,176			28,966
Distribution	25,772			29,835			29,695			28,170
Special charges	4,776			—			7,853			—
Loss on disposal of assets	1,105			1,493			516			1,054
Other operating	77,703			102,885			87,965			79,267
Total operating expenses	531,615			568,873			583,353			574,886

Operating income	58,342			131,312			103,874			91,296

Other (income) expense:
Interest expense	12,473			13,746			15,018			16,065
Capitalized interest	(3,580		)	(3,342		)	(3,203		)	(3,668		)
Interest income	(1,313		)	(1,828		)	(2,605		)	(2,990		)
Other expense	3			104			114			145
Total other (income) expense	7,583			8,680			9,324			9,552

Income before income taxes	50,759			122,632			94,550			81,744
Provision (benefit) for income taxes	19,498			45,391			34,506			(165,231		)

Net income	$	31,261		$	77,241		$	60,044		$	246,975
Basic earnings per share	$	0.45		$	1.11		$	0.87		$	3.59
Diluted earnings per share	$	0.45		$	1.11		$	0.86		$	3.58

The following table shows quarterly adjustments made due to the adoption of ASU 2014-09 on the statements of operations for 2017.



				Adjustments for the Quarter Ended
	Full Year 2017 As Reported			March 31, 2017			June 30, 2017			September 30, 2017			December 31, 2017			Full Year 2017 Adjusted
	(in thousands, except share and per share data)
Operating revenues:
Passenger	$	1,366,034		$	272,525		$	308,959		$	312,865		$	312,504		$	2,572,887
Other	1,281,632			(274,314		)	(310,455		)	(312,869		)	(313,329		)	70,665
Total operating revenues	2,647,666			(1,789		)	(1,496		)	(4		)	(825		)	2,643,552

Operating expenses:
Aircraft fuel	615,581			—			—			—			—			615,581
Salaries, wages and benefits	527,959			—			—			—			—			527,959
Aircraft rent	205,852			—			—			—			—			205,852
Landing fees and other rents	180,655			—			—			—			—			180,655
Depreciation and amortization	140,152			—			—			—			—			140,152
Maintenance, materials and repairs	110,439			—			—			—			—			110,439
Distribution	113,620			(726		)	(73		)	226			425			113,472
Special charges	12,629			—			—			—			—			12,629
Loss on disposal of assets	4,168			—			—			—			—			4,168
Other operating	347,820			—			—			—			—			347,820
Total operating expenses	2,258,875			(726		)	(73		)	226			425			2,258,727

Operating income	388,791			(1,063		)	(1,423		)	(230		)	(1,250		)	384,825

Other (income) expense:
Interest expense	57,302			—			—			—			—			57,302
Capitalized interest	(13,793		)	—			—			—			—			(13,793		)
Interest income	(8,736		)	—			—			—			—			(8,736		)
Other expense	366			—			—			—			—			366
Total other (income) expense	35,139			—			—			—			—			35,139

Income before income taxes	353,652			(1,063		)	(1,423		)	(230		)	(1,250		)	349,686
Provision (benefit) for income taxes	(66,954		)	(389		)	(522		)	(84		)	2,113			(65,836		)

Net income	$	420,606		$	(674	)	$	(901	)	$	(146	)	$	(3,363	)	$	415,522
Basic earnings per share	$	6.08		$	(0.01	)	$	(0.01	)	$	—		$	(0.05	)	$	6.00
Diluted earnings per share	$	6.06		$	(0.01	)	$	(0.01	)	$	—		$	(0.05	)	$	5.99

The following tables show adjustments made due to the adoption of ASU 2014-09 on the December 31, 2017 and 2016 balance sheets. Previously reported results were derived from audited financial statements included in Company's Annual Report on Form 10-K for the fiscal years ended December 31, 2017 and December 31, 2016, as applicable.



	December 31, 2017
	(in thousands)
	As Reported			Topic 606 Adjustment			As Adjusted
Assets
Current assets:
Cash and cash equivalents	$	800,849		$	—		$	800,849
Short-term investment securities	100,937			—			100,937
Accounts receivable, net	49,323			—			49,323
Aircraft maintenance deposits, net	175,615			—			175,615
Income tax receivable	69,844			—			69,844
Prepaid expenses and other current assets	83,692			1,850			85,542
Total current assets	1,280,260			1,850			1,282,110

Property and equipment:
Flight equipment	2,291,110			—			2,291,110
Ground property and equipment	155,166			—			155,166
Less accumulated depreciation	(207,808		)	—			(207,808		)
	2,238,468			—			2,238,468
Deposits on flight equipment purchase contracts	253,687			—			253,687
Long-term aircraft maintenance deposits	150,617			—			150,617
Deferred heavy maintenance, net	99,915			—			99,915
Other long-term assets	121,003			—			121,003
Total assets	$	4,143,950		$	1,850		$	4,145,800

Liabilities and shareholders’ equity
Current liabilities:
Accounts payable	$	22,822		$	—		$	22,822
Air traffic liability	246,404			17,307			263,711
Current maturities of long-term debt	115,430			—			115,430
Other current liabilities	262,370			—			262,370
Total current liabilities	647,026			17,307			664,333

Long-term debt, less current maturities	1,387,498			—			1,387,498
Deferred income taxes	313,140			(4,326		)	308,814
Deferred gains and other long-term liabilities	19,205			3,376			22,581
Shareholders’ equity:
Common stock: Common stock, $0.0001 par value, 240,000,000 shares authorized at December 31, 2017; 69,770,795 issued and 68,196,964 outstanding as of December 31, 2017	7			—			7
Additional paid-in-capital	360,153			—			360,153
Treasury stock, at cost: 1,573,831 shares as of December 31, 2017	(65,854		)	—			(65,854		)
Retained earnings	1,484,239			(14,507		)	1,469,732
Accumulated other comprehensive income (loss)	(1,464		)	—			(1,464		)
Total shareholders’ equity	1,777,081			(14,507		)	1,762,574
Total liabilities and shareholders’ equity	$	4,143,950		$	1,850		$	4,145,800



	December 31, 2016
	(in thousands)
	As Reported			Topic 606 Adjustment			As Adjusted
Assets
Current assets:
Cash and cash equivalents	$	700,900		$	—		$	700,900
Short-term investment securities	100,155			—			100,155
Accounts receivable, net	41,136			—			41,136
Aircraft maintenance deposits, net	87,035			—			87,035
Income tax receivable	—			—			—
Prepaid expenses and other current assets	46,619			1,702			48,321
Total current assets	975,845			1,702			977,547

Property and equipment:
Flight equipment	1,461,525			—			1,461,525
Ground property and equipment	126,206			—			126,206
Less accumulated depreciation	(122,509		)	—			(122,509		)
	1,465,222			—			1,465,222
Deposits on flight equipment purchase contracts	325,688			—			325,688
Long-term aircraft maintenance deposits	199,415			—			199,415
Deferred heavy maintenance, net	75,534			—			75,534
Other long-term assets	110,223			—			110,223
Total assets	$	3,151,927		$	1,702		$	3,153,629

Liabilities and shareholders’ equity
Current liabilities:
Accounts payable	$	15,193		$	—		$	15,193
Air traffic liability	206,392			13,792			220,184
Current maturities of long-term debt	84,354			—			84,354
Other current liabilities	226,011			—			226,011
Total current liabilities	531,950			13,792			545,742

Long-term debt, less current maturities	897,359			—			897,359
Deferred income taxes	308,143			(5,443		)	302,700
Deferred gains and other long-term liabilities	19,868			2,776			22,644
Shareholders’ equity:
Common stock: Common stock, $0.0001 par value, 240,000,000 shares authorized at December 31, 2016; 73,549,872 issued and 69,326,202 outstanding as of December 31, 2016	7			—			7
Additional paid-in-capital	551,004			—			551,004
Treasury stock, at cost: 4,223,670 shares as of December 31, 2016	(218,692		)	—			(218,692		)
Retained earnings	1,063,633			(9,423		)	1,054,210
Accumulated other comprehensive income (loss)	(1,345		)	—			(1,345		)
Total shareholders’ equity	1,394,607			(9,423		)	1,385,184
Total liabilities and shareholders’ equity	$	3,151,927		$	1,702		$	3,153,629