AIRCRAFT - Aircraft Fleet (Details) - aircraft	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization [Roll Forward]
Balance at beginning of period	70	63
Additions	2	3
Reclassifications	0	0
Removals	0	0
Balance at end of period	72	66
Passenger
Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization [Roll Forward]
Balance at beginning of period	47	45
Additions	0	0
Reclassifications	0	0
Removals	0	0
Balance at end of period	47	45
Passenger | Owned
Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization [Roll Forward]
Balance at beginning of period	35	34
Additions	0	0
Reclassifications	0	0
Removals	0	0
Balance at end of period	35	34
Passenger | Finance leases
Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization [Roll Forward]
Balance at beginning of period	12	11
Additions	0	0
Reclassifications	0	0
Removals	0	0
Balance at end of period	12	11
Cargo | Aircrafts Operated For Amazon
Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization [Roll Forward]
Balance at beginning of period	20	12
Additions	2	3
Reclassifications	0	0
Removals	0	0
Balance at end of period	22	15
Other Property | Owned Aircraft Held for Operating Lease
Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization [Roll Forward]
Balance at end of period	2
Other Property | Owned Aircraft Held for Operating Lease
Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization [Roll Forward]
Balance at beginning of period	2	4
Additions	0	0
Reclassifications	0	0
Removals	0	0
Balance at end of period	2	4
Other Property | Subleased Aircraft
Property, Plant, and Equipment, before Accumulated Depreciation, Depletion, and Amortization [Roll Forward]
Balance at beginning of period	1	2
Additions	0	0
Reclassifications	0	0
Removals	0	0
Balance at end of period	1	2