COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2024 aircraft	Jun. 30, 2023 aircraft	Dec. 31, 2023 USD ($)
Future aircraft purchase commitments
Future Purchase Commitments
Future aircraft purchase commitments | $			$ 17,530
A330-900
Future Purchase Commitments
Number of aircraft agreed to be acquired		1
A220-300
Future Purchase Commitments
Number of aircraft purchase rights exercised		26
A350-1000 | Subsequent event
Future Purchase Commitments
Number of aircraft agreed to be acquired	20
A350-1000 Widebody | Subsequent event
Future Purchase Commitments
Number of optional additional aircrafts	20