Summary of Significant Accounting Policies - Passenger Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Air traffic liability	$ 383,751	$ 429,618
Total operating revenues	$ 5,362,549	5,068,447	$ 3,230,775
Credit shell term of expiration	90 days
Fare
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 2,338,191	2,455,817	1,422,927
Non-fare revenue
Disaggregation of Revenue [Line Items]
Total operating revenues	2,929,970	2,533,548	1,752,875
Passenger
Disaggregation of Revenue [Line Items]
Total operating revenues	5,268,161	4,989,365	3,175,802
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 94,388	$ 79,082	$ 54,973