Frontier Group Holdings, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2025

or

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from __ to __

Commission File Number:001-40304

Frontier Group Holdings, Inc.

(Exact name of registrant as specified in its charter)

4545 Airport Way

Denver, CO 80239

(720)374-4550

(Address of principal executive offices, including zip code, and Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐No ☒

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☒

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined by Rule 12b-2 of the Act). Yes☐ No ☒

The aggregate market value of the common stock held by non-affiliates of the registrant was approximately $204 million, computed by reference to the closing sale price of the registrant’s common stock on the Nasdaq Global Select Market on June 30, 2025, the last business day of the registrant’s most recently completed second fiscal quarter.

The registrant had 229,609,718 shares of common stock, $0.001 par value per share, outstanding as of February 13, 2026.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant's definitive Proxy Statement relating to its 2026 Annual Meeting of Stockholders are incorporated by reference in Part III of this Annual Report on Form 10-K to the extent stated herein. Such Proxy Statement will be filed with the Securities and Exchange Commission within 120 days of the registrant's fiscal year ended December 31, 2025.

TABLE OF CONTENTS

Cautionary Statement Regarding Forward-Looking Statements

Certain statements in this Annual Report on Form 10-K should be considered forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and the Private Securities Litigation Reform Act of 1995. These forward-looking statements are based on our current expectations and beliefs with respect to certain current and future events and anticipated financial and operating performance. Words such as “may,” “might,” “will,” “should,” “could,” “would,” “expect,” “intends,” “plan,” “anticipate,” “believe,” “estimate,” “project,” “targets,” “predict,” “potential,” and similar expressions intended to identify forward-looking statements. Additionally, forward-looking statements include statements that do not relate solely to historical facts, such as statements which identify uncertainties or trends, discuss the possible future effects of current known trends or uncertainties, or which indicate that the future effects of known trends or uncertainties cannot be predicted, guaranteed or assured. This Annual Report on Form 10-K contains forward-looking statements based upon current plans, expectations and beliefs involving risks and uncertainties. Our actual results may differ materially from those anticipated in these forward-looking statements as a result of various factors, including those set forth in Part I, Item 1A, “Risk Factors”, Part II, Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and other factors set forth from time to time under the sections captioned “Risk Factors” in our reports and other documents filed with the Securities and Exchange Commission (the “SEC”). Furthermore, such forward-looking statements speak only as of the date of this report. Except as required by law, we undertake no obligation to update any forward-looking statements to reflect events or circumstances after the date of such statements.

Summary Risk Factors

Our business is subject to a number of risks and uncertainties that may affect our business, results of operations and financial condition, or the trading price of our common stock or other securities. We caution the reader that these risk factors may not be exhaustive. We operate in a continually changing business environment, and new risks and uncertainties emerge from time to time. Management cannot predict such new risks and uncertainties, nor can it assess the extent to which any of the risk factors below or any such new risks and uncertainties, or any combination thereof, may impact our business. The risks identified below are more fully described in Part I, Item 1A, “Risk Factors.” Such factors include:

Risks Related to Our Industry

•changes in economic conditions affecting demand for air travel, including from economic slowdowns, recessions, inflationary pressures, rising interest rates, financial market fluctuations, supply chain challenges, reduced credit availability, and global conflict;

•the ability to attract and retain qualified personnel at reasonable costs or maintain our company culture;

•the ability to operate in an exceedingly competitive industry against legacy network airlines, low-cost carriers (“LCCs”) and other ultra low-cost carriers (“ULCCs”);

•the price and availability of aircraft fuel;

•compliance with, and any changes in, governmental regulation;

•any restrictions on or increased taxes applicable to charges for non-fare products and services paid by airline passengers or the imposition of burdensome consumer protection regulations or laws;

•the impact of climate change and related laws, regulations, litigation and changing consumer preferences;

•environmental and noise laws and regulations;

•factors beyond our control, including air traffic congestion at airports, air traffic control inefficiencies, government shutdowns, major construction or improvement projects at airports, aircraft and engine defects, U.S. Federal Aviation Administration (“FAA”) grounding of aircraft, adverse weather conditions, increased security measures, new travel-related identification requirements, taxes or fees, natural disasters or outbreaks of disease;

•competition from air travel substitutes;

•future public health threats or outbreaks of disease, including pandemics similar to the COVID-19 pandemic, as well as measures to reduce the spread of such disease and the related economic impact, that negatively impact the demand for air travel;

•threatened or actual terrorist attacks or security concerns;

•decline in, or suspension of, funding or operations of the U.S. federal government or its agencies;

•our presence in international emerging markets that may experience political or economic instability and a failure to comply with legal requirements; and

•increases in insurance costs or inability to secure adequate insurance coverage.

Risks Related to Our Business

•our failure to implement our business strategy successfully;

•our ability to control our costs and maintain a competitive cost structure;

•our ability to grow or maintain our unit revenues or maintain our non-fare revenues;

•our ability to grow our fleet is dependent on a limited number of suppliers;

•the long-term nature of our fleet and order book which commits us to Airbus S.A.S. (“Airbus”) aircraft and the engines available for such aircraft for a substantial period of time into the future;

•any increased labor costs, union disputes and other labor-related disruptions;

•our inability to expand or operate reliably and efficiently out of airports where we maintain a large presence;

•any damage to our reputation or brand image;

•our reputation and business being adversely affected in the event of an emergency, accident, or similar public incident involving our aircraft or personnel;

•increasing scrutiny and evolving expectations from customers, regulators, investors and other stakeholders or competitors with respect to our environmental, social and governance practices, commitments or the quality or progress thereof;

•any negative publicity regarding our customer service;

•our inability to maintain a high daily aircraft utilization rate;

•being highly dependent upon cash balances and operating cash flows;

•our ability to obtain financing or access capital markets;

•our maintenance obligations;

•aircraft-related fixed obligations and obligations under other debt arrangements that could impair our liquidity;

•our reliance on third-party specialists and other commercial partners to perform functions integral to our operations;

•our reliance on third-party distribution channels to distribute a portion of our airline tickets;

•our reliance on technology and automated systems to operate our business;

•unauthorized use or user exploitation of our IT Systems (as defined below in 1A Risk Factors);

•our dependence on select large markets;

•changes in legislation, regulation and government policy;

•the impact of U.S. tax legislation;

•our ability to use our net operating loss carryforwards;

• any tariffs imposed on commercial aircraft and related parts;

•the loss of key personnel;

•our reliance on our private equity sponsor;

•fluctuations in our quarterly results of operations; and

•our lack of membership in a marketing alliance or codeshare arrangement.

Risks Related to Owning Our Common Stock

•the market price for our common stock may be volatile;

•analysts may not publish reports or publish negative reports about our business;

•the issuance or sale of our common stock could depress the trading price;

•the value of our common stock may be affected by additional issuances of common stock or sales;

•our anti-takeover provisions may delay or prevent a change of control;

•our exclusive forum provisions in our governing documents;

•our renouncement of our interest and expectancy in certain corporate opportunities;

•our limits on ownership, control and voting by non-U.S. citizens; and

•our reliance on dividends, distributions and other payments from our subsidiaries.

General Risk Factors

•potential involvement in litigation that could have a material adverse effect on our business.