Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 461,279	$ 771,081
Refunds issued	31,900	43,700
Air traffic liability	$ 509,172		$ 401,966
Minimum
Disaggregation of Revenue [Line Items]
Credit shell term expiration	60 days
Maximum
Disaggregation of Revenue [Line Items]
Credit shell term expiration	12 months
DOT—Domestic
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 408,693	697,828
DOT—Latin America
Disaggregation of Revenue [Line Items]
Total operating revenues	52,586	73,253
Passenger
Disaggregation of Revenue [Line Items]
Total operating revenues	450,335	753,550
Fare
Disaggregation of Revenue [Line Items]
Total operating revenues	174,287	321,447
Non-fare
Disaggregation of Revenue [Line Items]
Total operating revenues	276,048	432,103
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 10,944	$ 17,531