UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): April 14, 2022 (April 13, 2022)

Frontier Group Holdings, Inc.

(Exact name of registrant as specified in its charter)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

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. ☐

On April 14, 2022, Frontier Group Holdings, Inc. made available to the media a statement regarding the status of the antitrust review process for its pending merger with Spirit Airlines, Inc. A copy of the statement is attached hereto as Exhibit 99.1 and incorporated herein by reference.

(d) Exhibits

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Exhibit 99.1

Frontier Airlines’ Statement Regarding HSR Second Request

On April 13, 2022, Frontier received a request for additional information from the U.S. Department of Justice (DOJ) with respect to its proposed merger with Spirit. A second request from the DOJ was expected for a transaction of this nature – any other airline combination would expect the same. Over the last several weeks, Frontier and Spirit have been voluntarily providing information to the DOJ in order to facilitate its review of the proposed transaction and will continue to do so over the coming months.

A combined Spirit and Frontier will deliver $1 billion in annual savings for consumers and offer even more ultra-low fares to more places. Together, we will create a true nationwide ultra-low fare competitor against the dominant ‘Big Four’ airlines and other high-cost airlines like JetBlue. In addition, the structure of the transaction will enable both Spirit and Frontier shareholders to benefit from the substantial upside potential of the combined company.

We look forward to demonstrating the consumer benefits inherent in the Frontier and Spirit combination at a time when JetBlue has made a proposal that would reduce competition and lead to more expensive travel for consumers. We can’t wait to bring even more ultra-low fares to more places. Consumers looking for affordable flight options across the country are counting on it.

No Offer or Solicitation

This communication is for informational purposes only and is not intended to and does not constitute an offer to sell, or the solicitation of an offer to subscribe for or buy, or a solicitation of any vote or approval in any jurisdiction, nor shall there be any sale, issuance or transfer of securities in any jurisdiction in which such offer, sale or solicitation would be unlawful, prior to registration or qualification under the securities laws of any such jurisdiction. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended, and otherwise in accordance with applicable law.

Important Additional Information Will be Filed with the SEC

Frontier has filed with the Securities and Exchange Commission (“SEC”) a Registration Statement on Form S-4 in connection with the proposed transaction (which Registration Statement has not yet been declared effective), that included a preliminary Information Statement/Prospectus of Frontier and a preliminary Proxy Statement of Spirit. The Registration Statement is not complete and will be further amended. Frontier and Spirit also plan to file other relevant documents with the SEC regarding the proposed transaction. INVESTORS AND STOCKHOLDERS ARE URGED TO READ THE REGISTRATION STATEMENT/ INFORMATION STATEMENT/ PROSPECTUS/ PROXY STATEMENT AND ANY OTHER RELEVANT DOCUMENTS TO BE FILED BY FRONTIER OR SPIRIT WITH THE SEC IN THEIR ENTIRETY CAREFULLY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT FRONTIER, SPIRIT, THE PROPOSED TRANSACTIONS AND RELATED MATTERS. Investors and stockholders will

be able to obtain free copies of the Registration Statement and the definitive Information Statement/Proxy Statement/Prospectus and other documents filed with the SEC by Frontier and Spirit through the website maintained by the SEC at www.sec.gov. In addition, investors and stockholders will be able to obtain free copies of the information statement and the proxy statement and other documents filed with the SEC by Frontier and Spirit on Frontier’s Investor Relations website at https://ir.flyfrontier.com and on Spirit’s Investor Relations website at https://ir.spirit.com.

Participants in the Solicitation

Frontier and Spirit, and certain of their respective directors and executive officers, may be deemed to be participants in the solicitation of proxies in respect of the proposed transactions contemplated by the Merger Agreement. Information regarding Frontier’s directors and executive officers is contained in Frontier’s definitive proxy statement, which was filed with the SEC on April 13, 2022. Information regarding Spirit’s directors and executive officers is contained in Spirit’s definitive proxy statement, which was filed with the SEC on March 30, 2022.

Cautionary Statement Regarding Forward-Looking Information

Certain statements in this communication, including statements concerning Frontier, Spirit, the proposed transactions and other matters, should be considered forward-looking within the meaning of the Securities Act of 1933, as amended, the Securities Exchange Act of 1934, as amended, and the Private Securities Litigation Reform Act of 1995. These forward-looking statements are based on Frontier’s and Spirit’s current expectations and beliefs with respect to certain current and future events and anticipated financial and operating performance. Such forward-looking statements are and will be subject to many risks and uncertainties relating to Frontier’s and Spirit’s operations and business environment that may cause actual results to differ materially from any future results expressed or implied in such forward looking statements. Words such as “expects,” “will,” “plans,” “intends,” “anticipates,” “indicates,” “remains,” “believes,” “estimates,” “forecast,” “guidance,” “outlook,” “goals,” “targets” and other similar expressions are 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. All forward-looking statements in this communication are based upon information available to Frontier and Spirit on the date of this communication. Frontier and Spirit undertake no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events, changed circumstances, or otherwise, except as required by applicable law.

Actual results could differ materially from these forward-looking statements due to numerous factors including, without limitation, the following: the occurrence of any event, change or other circumstances that could give rise to the right of one or both of the parties to terminate the merger agreement; failure to obtain applicable regulatory or Spirit stockholder approval in a timely manner or otherwise; failure to satisfy other closing conditions to the proposed transactions; failure of the parties to consummate the transaction; risks that the new businesses will not be integrated

successfully or that the combined companies will not realize estimated cost savings, value of certain tax assets, synergies and growth, or that such benefits may take longer to realize than expected; failure to realize anticipated benefits of the combined operations; risks relating to unanticipated costs of integration; demand for the combined company’s services; the growth, change and competitive landscape of the markets in which the combined company participates; expected seasonality trends; diversion of managements’ attention from ongoing business operations and opportunities; potential adverse reactions or changes to business or employee relationships, including those resulting from the announcement or completion of the transaction; risks related to investor and rating agency perceptions of each of the parties and their respective business, operations, financial condition and the industry in which they operate; risks related to the potential impact of general economic, political and market factors on the companies or the proposed transaction; that Frontier’s cash and cash equivalents balances, together with the availability under certain credit facilities made available to Frontier and certain of its subsidiaries under its existing credit agreements, will be sufficient to fund Frontier’s operations including capital expenditures over the next 12 months; Frontier’s expectation that based on the information presently known to management, the potential liability related to Frontier’s current litigation will not have a material adverse effect on its financial condition, cash flows or results of operations; that the COVID-19 pandemic will continue to impact the businesses of the companies; ongoing and increase in costs related to IT network security; and other risks and uncertainties set forth from time to time under the sections captioned “Risk Factors” in Frontier’s and Spirit’s reports and other documents filed with the SEC from time to time, including their Annual Reports on Form 10-K and Quarterly Reports on Form 10-Q.