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DEBT - Long-term Debt (Details)	1 Months Ended	3 Months Ended
DEBT - Long-term Debt (Details)	Dec. 31, 2019 aircraft	Jun. 30, 2025 aircraft	Dec. 31, 2024 USD ($) aircraft	Jun. 30, 2024 aircraft	Dec. 31, 2023 aircraft	Jun. 30, 2023 USD ($) aircraft	Mar. 31, 2022 USD ($) aircraft	Dec. 31, 2020 USD ($)
DEBT
Number of aircraft		69	63	63	60
Owned Aircraft Held for Operating Lease \| Other Property
DEBT
Number of aircraft		3	4			5
Owned Aircraft Held for Operating Lease \| Other Property
DEBT
Number of aircraft				5	5
Line of Credit \| Secured Debt
DEBT
Margin (as a percent)		0.10%
Interest rate		7.70%
Loan-to -value ratio		75.00%
Line of Credit \| Secured Debt \| Owned Aircraft Held for Operating Lease
DEBT
Interest rate		8.20%
Line of Credit \| Secured Debt \| Maximum
DEBT
Margin (as a percent)		3.75%
Line of Credit \| Secured Debt \| Minimum
DEBT
Margin (as a percent)		3.25%
Term Loan \| Notes payable
DEBT
Face amount \| $						$ 119,200,000
2022-1 EETC \| Notes payable
DEBT
Face amount \| $							$ 188,277,000
Number of aircraft financed by debt							13
Weighted average interest rate		5.05%
2022-1 EETC \| Notes payable \| Maximum
DEBT
Interest rate		5.75%
2022-1 EETC \| Notes payable \| Minimum
DEBT
Interest rate		4.84%
2019-1 EETC \| Notes payable
DEBT
Face amount \| $								$ 248,587,000
Weighted average interest rate		5.43%
Number of used aircrafts purchased or refinanced	13
2019-1 EETC \| Notes payable \| Maximum
DEBT
Interest rate		7.10%
2019-1 EETC \| Notes payable \| Minimum
DEBT
Interest rate		4.13%
Notes payable under the Company's 2019-1 EETC agreement \| Notes payable
DEBT
Face amount \| $			$ 60,000,000