Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of Spirit Airlines, Inc. (“Spirit”) and its consolidated subsidiaries (together with Spirit, the “Company”). These unaudited condensed consolidated financial statements reflect all normal recurring adjustments that management believes are necessary to fairly present the financial position, results of operations and cash flows of the Company for the respective periods presented. Certain information and footnote disclosures normally included in the audited annual financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission for Form 10-Q. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements of the Company and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2023 filed with the Securities and Exchange Commission on February 9, 2024. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect both the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from these estimates. The interim results reflected in the unaudited condensed consolidated financial statements are not necessarily indicative of the results that may be expected for other interim periods or for the full year. The air transportation business is subject to significant seasonal fluctuations as demand is generally greater in the second and third quarters of each year. The air transportation business is volatile and highly affected by economic cycles and trends. Going Concern The Company has been impacted by an increasingly challenging pricing environment. Moreover, the expected short-term impact of certain policy changes, such as the removal of change and cancel fees, have negatively affected revenue performance. In addition, challenging market conditions, including increasing costs, have impacted the Company's performance. The Company expects these trends to continue for at least the remainder of 2024, which creates uncertainty in operating results. In addition, the Company had been in discussions with representatives of certain of its bondholders to negotiate the terms for refinancing or extending its existing 8.00% senior secured notes due in September 2025, as well as representatives of certain of its convertible notes due 2026. On November 18, 2024, the Company entered into a Restructuring Support Agreement (as defined below) with certain of its bondholders. The Company has evaluated whether there are any conditions and events, considered in the aggregate, that raise substantial doubt about its ability to continue as a going concern within one year from the filing of this Quarterly Report on Form 10-Q. On November 18, 2024 (the “Petition Date”), Spirit commenced a voluntary case (the “Chapter 11 Case”) under Chapter 11 of Title 11 of the United States Code (the “Bankruptcy Code”) in the United States Bankruptcy Court for the Southern District of New York (the “Bankruptcy Court”). Under the terms of the Restructuring Support Agreement (as defined below), certain of Spirit’s subsidiaries (together with Spirit, the “Company Parties”) plan to file voluntary petitions for relief under the Bankruptcy Code on or before November 29, 2024 (together with the Chapter 11 Case, the “Chapter 11 Cases”). Since the Petition Date, Spirit has been operating its businesses as a debtor-in-possession under the jurisdiction of the Bankruptcy Court in accordance with the applicable provisions of the Bankruptcy Code and orders of the Bankruptcy Court. Spirit received approval from the Bankruptcy Court for a variety of “first day” motions to continue its ordinary course operations during the Chapter 11 Case. However, for the duration of the Chapter 11 Cases, the Company’s operations and ability to develop and execute its business plan, its financial condition, liquidity and its continuation as a going concern are subject to a high degree of risk and uncertainty associated with the Chapter 11 Cases. The outcome of the Chapter 11 Cases is dependent upon factors that are outside of the Company’s control, including actions of the Bankruptcy Court. The Company can give no assurances that it will be able to secure additional sources of funds to support its operations, or, if such funds are available to the Company, that such additional financing will be sufficient to meet its needs. Based on such evaluation and management’s current plans, which are subject to change and include implementation of discretionary cost reduction strategies and the sale of certain of its owned aircraft, management believes there is substantial doubt about the Company’s ability to continue as a going concern. The Company’s condensed consolidated financial statements have been prepared assuming that it will continue to operate as a going concern, which contemplates the Company’s ability to successfully implement the plan of reorganization, its continuity of operations, realization of assets and liquidation of liabilities in the normal course of business and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from uncertainty related to its ability to continue as a going concern. For additional information, refer to Note 14, Subsequent Events.