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v3.25.3

Long-Term Debt, Finance Leases, and Other Borrowings - Additional Information (Detail) |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Mar. 18, 2025 | Dec. 23, 2024 | Sep. 06, 2023 USD ($) | Dec. 27, 2022 USD ($) | Oct. 30, 2020 USD ($) $ / shares shares | Dec. 31, 2015 USD ($) | Sep. 30, 2024 USD ($) | Sep. 30, 2025 USD ($) $ / shares | Sep. 30, 2024 USD ($) | Jun. 30, 2023 USD ($) | Dec. 31, 2024 USD ($) | Dec. 31, 2020 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Property and equipment-gross |  |  |  |  |  |  |  | $ 59,884,000 |  |  | $ 329,619,000 |
Long-Term Debt |  |  |  |  |  |  |  | 95,021,000 |  |  | 227,061,000 |
Current portion of long-term debt |  |  |  |  |  |  |  | $ 68,009,000 |  |  | $ 143,275,000 |
Gain on investments |  |  |  |  |  |  | $ 1,578,000 |  | $ 8,032,000 |  |  |
Warrants of common stock exercise price | $ / shares |  |  |  |  |  |  |  | $ 3.98 |  |  |  |
Treasury Loan [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Calculated collateral coverage ratio |  |  |  |  | 1.55 |  |  |  |  |  |  |
Treasury Loan [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Additional collateral coverage ratio |  |  |  |  | 1.55 |  |  |  |  |  |  |
Loan Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Warrants to purchase shares of common stock | shares |  |  |  |  | 4,899,497 |  |  |  |  |  |  |
Warrants of common stock exercise price | $ / shares |  |  |  |  | $ 3.98 |  |  |  |  |  |  |
Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Permitted amount to redraw from existing credit facility |  |  | $ 7,900,000 |  |  |  |  |  |  |  |  |
Revolving Credit Facility [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Revolving commitments |  |  | 50,700,000 |  |  |  |  |  |  |  |  |
Revolving Credit Facility [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Revolving commitments |  |  | $ 30,700,000 |  |  |  |  |  |  |  |  |
United Capacity Purchase Agreement [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  | 3.50% | 3.50% |  |  |  |  |  |  |  |
Revolving loan |  |  |  | $ 10,500,000 |  |  |  |  |  |  |  |
Covenant capping restricted payments |  |  |  | 5,000,000 |  |  |  |  |  |  |  |
Revolving commitments |  |  |  | $ 30,700,000 |  |  |  |  |  |  |  |
Rental coverage ratio |  |  |  | 1 |  |  |  |  |  |  |  |
United Capacity Purchase Agreement [Member] | Revolving Credit Facility [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Amount required |  |  |  |  |  |  |  |  |  | $ 15,000,000 |  |
United Capacity Purchase Agreement [Member] | Revolving Credit Facility [Member] | SOFR [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  | 4.50% | 4.50% |  |  |  |  |  |  |  |
United Capacity Purchase Agreement [Member] | United [Member] | Revolving Credit Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Amount funded by company |  |  |  |  |  |  |  |  |  | $ 25,500,000 |  |
Secured Term Loan Facility [Member] | Loan Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Secured term loan facility, maximum borrowing capacity |  |  |  |  | $ 200,000,000.0 |  |  |  |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  | Oct. 30, 2025 |  |  |  |
Secured Term Loan Facility [Member] | Loan Agreement [Member] | Treasury Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Long term debt, basis spread on variable rate |  |  |  |  | 3.50% |  |  |  |  |  |  |
Percentage of all in rate |  |  |  |  |  |  |  | 8.08% |  |  |  |
Secured term loan facility, amount borrowed |  |  |  |  |  |  |  |  |  |  |  | $ 195,000,000.0
Secured term loan facility, additional amount borrowed |  |  |  |  |  |  |  | $ 0 |  |  |  |
Debt instrument, maturity date |  |  |  |  | Oct. 30, 2025 |  |  |  |  |  |  |
UST Loan [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, maturity date |  |  |  |  |  |  |  | Oct. 30, 2025 |  |  |  |
UST Loan [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Minimum Collateral Coverage Ratio 1 | 91 | 99 |  |  |  |  |  |  |  |  |  |
E175 Aircraft [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Remaining Balance |  |  |  |  |  | $ 73,400,000 |  |  |  |  |  |
Aircraft and Equipment [Member] | Pledged as Collateral [Member] |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Property and equipment-gross |  |  |  |  |  |  |  | $ 47,000,000 |  |  |  |

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