Operating Revenues (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026 USD ($) aircraft	Jun. 30, 2025 USD ($)	Jun. 30, 2026 USD ($) aircraft	Jun. 30, 2025 USD ($)	Dec. 31, 2025 USD ($)
Agreements with other airlines
Percentage of ASMs flown under fixed-fee arrangements			81.90%	85.50%
Percentage of ASMs flown under pro-rate arrangements			18.10%	14.50%
Rental income under operating leases
Operating lease fixed revenue | $	$ 15,507	$ 16,697	$ 33,249	$ 32,762
Operating lease variable revenue | $	9,265	8,526	16,710	15,535
Total operating revenues | $	1,102,751	1,035,227	2,115,928	1,983,682
Future minimum rental income
July 2026 - December 2026 | $	24,506		24,506
2027 | $	45,657		45,657
2028 | $	44,277		44,277
2029 | $	42,748		42,748
2030 | $	26,459		26,459
Thereafter | $	2,723		2,723
Total future minimum rental income under operating leases | $	186,370		186,370
Property and equipment and related assets | $	5,945,352		5,945,352		$ 5,842,968
Gross receivables current | $	192,500		192,500		163,300
Gross receivables Non-current | $	252,700		252,700		$ 266,300
Balance | $			22,509
Adjustments to credit loss reserves | $			(1,150)
Write-offs charged against allowance | $			(94)
Balance | $	21,265		$ 21,265
Minimum
Agreements with other airlines
EAS contract term			2 years
Maximum
Agreements with other airlines
EAS contract term			3 years
Aircraft in schedule service or under contract
Future minimum rental income
Number of aircraft			517
United
Future minimum rental income
Number of aircraft			239
United | United Express Prorate Agreement
Future minimum rental income
Agreement term			120 days
Delta
Future minimum rental income
Number of aircraft			139
Delta | Delta Connection Prorate Agreement
Future minimum rental income
Agreement term			30 days
American
Future minimum rental income
Number of aircraft			96
American | American Prorate Agreement
Future minimum rental income
Agreement term			180 days
Jet aircraft and spare engines leased to third parties
Future minimum rental income
Property and equipment and related assets | $	$ 233,400		$ 233,400
CRJ | Delta Connection Agreements
Future minimum rental income
Number of aircraft anticipated to be removed			16
CRJ 200 | United | United Express Agreements
Future minimum rental income
Number of aircraft			36
CRJ 200 | United | United Express Prorate Agreement
Future minimum rental income
Number of aircraft			37
CRJ 550 | United Express Agreements
Future minimum rental income
Number of new aircraft ordered	12		12
CRJ 550 | United | United Express Agreements
Future minimum rental income
Number of aircraft			36
CRJ 550 | Delta | Delta Connection Prorate Agreement
Future minimum rental income
Number of aircraft			16
CRJ700/E170 | United | United Express Agreements
Future minimum rental income
Number of aircraft			8
CRJ 700 | American Capacity Purchase Agreement
Future minimum rental income
Number of aircraft anticipated to be removed			11
CRJ 700 | Delta | Delta Connection Agreements
Future minimum rental income
Number of aircraft			2
CRJ 700 | American | American Capacity Purchase Agreement
Future minimum rental income
Number of aircraft			63
CRJ 700 | American | American Prorate Agreement
Future minimum rental income
Number of aircraft			4
CRJ 900 | Delta | Delta Connection Agreements
Future minimum rental income
Number of aircraft			34
CRJ 900 | American | American Capacity Purchase Agreement
Future minimum rental income
Number of aircraft			5
CRJ 900 | American | American Prorate Agreement
Future minimum rental income
Number of aircraft			4
E175 | United Express Agreements
Future minimum rental income
Number of new aircraft ordered	7		7
E175 | Delta Connection Agreements
Future minimum rental income
Number of new aircraft ordered	16		16
Number of aircraft scheduled for delivery in 2027	10		10
Number of aircraft to be placed in service			16
Number of aircraft scheduled for delivery in 2028	6		6
E175 | American Capacity Purchase Agreement
Future minimum rental income
Number of new aircraft ordered	11		11
Number of aircraft scheduled for delivery in remainder of fiscal year	4		4
Number of aircraft scheduled for delivery in 2027	7		7
Number of aircraft to be placed in service			11
E175 | United | United Express Agreements
Future minimum rental income
Number of aircraft			122
E175 | Delta | Delta Connection Agreements
Future minimum rental income
Number of aircraft			87
E175 | American | American Capacity Purchase Agreement
Future minimum rental income
Number of aircraft			20
E175 | Alaska | Alaska Capacity Purchase Agreement
Future minimum rental income
Number of aircraft			43
Flying agreements revenue
Rental income under operating leases
Total operating revenues | $	$ 1,064,549	987,511	$ 2,042,434	1,903,505
Capacity purchase agreements flight operations revenue (non-lease component)
Rental income under operating leases
Total operating revenues | $	677,213	682,948	1,311,082	1,322,101
Capacity purchase agreements fixed aircraft lease revenue
Rental income under operating leases
Total operating revenues | $	107,579	104,220	212,034	215,208
Capacity purchase agreements variable aircraft lease revenue
Rental income under operating leases
Total operating revenues | $	78,913	54,898	150,286	89,937
Prorate agreements and charter revenue
Rental income under operating leases
Total operating revenues | $	200,844	145,445	369,032	276,259
Airport customer service and other revenue
Rental income under operating leases
Total operating revenues | $	13,430	22,493	23,535	31,880
Lease, airport services and other.
Rental income under operating leases
Total operating revenues | $	$ 38,202	$ 47,716	$ 73,494	$ 80,177