Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2023

Accounting Policies [Abstract]

Schedule of Depreciable Lives Used for the Principal Depreciable Asset Classifications and Components of Depreciation and Amortization

The depreciable lives used for the principal depreciable asset classifications are:

	Estimated Useful Life
Aircraft, engines and flight simulators	25
Spare rotables and flight assemblies	7 to 25 years
Other equipment and vehicles	5 to 7 years
Internal use software	3 to 10 years
Finance leases	Lease term or estimated useful life of the asset
Leasehold improvements	Lesser of lease term or estimated useful life of the improvement
Buildings	Lesser of lease term or 30 years

The following table illustrates the components of depreciation and amortization expense:

	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Depreciation	$	218,106	$	199,118	$	193,079
Amortization of heavy maintenance	79,768		96,707		91,929
Amortization of capitalized software	22,998		17,265		12,203
Total depreciation and amortization	$	320,872	$	313,090	$	297,211

Schedule of Revenue Disaggregation

The following table shows disaggregated operating revenues for the twelve months ended December 31, 2023, 2022 and 2021:

	Twelve Months Ended December 31,
	2023		2022		2021
	(in thousands)
Operating revenues:
Fare	$	2,338,191	$	2,455,817	$	1,422,927
Non-fare	2,929,970		2,533,548		1,752,875
Total passenger revenues	5,268,161		4,989,365		3,175,802
Other	94,388		79,082		54,973
Total operating revenues	$	5,362,549	$	5,068,447	$	3,230,775

Schedule of Total Cash Proceeds Received from the Sale of Mileage Credit

The following table illustrates total cash proceeds received from the sale of points and the portion of such proceeds recognized in non-ticket revenue immediately as marketing component:

	Consideration received from credit card loyalty programs		Portion of proceeds recognized immediately as marketing component
Year Ended	(in thousands)
December 31, 2023	$	93,147	$	48,071
December 31, 2022	80,970		40,987
December 31, 2021	48,035		23,681

Schedule of Aircraft Maintenance Expense

The table below summarizes the components of the Company’s maintenance cost:

	Year Ended December 31,
	2023		2022		2021
	(in thousands)
Utilization-based maintenance expense	$	117,458	$	97,930	$	81,591
Non-utilization-based maintenance expense	105,881		89,890		77,911
Total maintenance, materials and repairs	$	223,339	$	187,820	$	159,502