8-K

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: December 8, 2025

Archer Aviation Inc.

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code: 650-272-3233

N/A

(Former Name or Former Address, if Changed Since Last Report)

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:

| o | Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) | | --- | --- || o | Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) | | --- | --- || o | Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) | | --- | --- || o | Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) | | --- | --- |

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  o

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.  o

Item 7.01 Other Events

Hawthorne Airport Acquisition Initial Closing

On December 8, 2025, the Company completed the previously announced acquisition of certain real estate assets giving it control of Hawthorne airport. A copy of the press release announcing the closing is attached hereto as Exhibit 99.1.

The information in this Item 7.01, including Exhibit 99.1, is furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to liabilities under that section, and shall not be deemed to be incorporated by reference into the filings of the registrant under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act, regardless of any general incorporation language in such filings.

Item 8.01 Other Events

On December 10, 2025, the Company filed a prospectus supplement pursuant to Rule 424(b) under the Securities Act with the Securities and Exchange Commission (the “SEC”) relating to the resale of 1,174,453 shares of Class A common stock, $0.0001 par value per share that were issued by the Company to the selling stockholder. The shares were issued pursuant to an Asset Purchase Agreement, dated November 18, 2025, by and among the parties named therein relating to the acquisition of certain intellectual property assets of Overair Inc. by the Company. The prospectus supplement forms a part of the Company’s Registration Statement on Form S-3 (No. 333-284812), which was originally filed with the SEC on February 11, 2025 (the “Registration Statement”).

A copy of the legal opinion of Fenwick & West LLP relating to the validity of the shares of Class A common stock is filed as Exhibit 5.1 to this Current Report on Form 8-K and is filed with reference to, and is hereby incorporated by reference into, the Registration Statement.

Item 9.01 Financial Statements and Exhibits.

(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_51

December 10, 2025 Archer Aviation Inc. 190 West Tasman Drive San Jose, California 95134 Re: Registration Statement on Form S-3ASR Ladies and Gentlemen: As counsel to Archer Aviation Inc., a Delaware Corporation (the “Company”), we deliver this opinion with respect to certain matters in connection with the resale from time to time of 1,174,453 shares (the “Shares”) of the Company’s Class A common stock, $0.0001 par value per share (“Class A Common Stock”), by the selling stockholder as described in the Prospectus (as defined below). The resale of the Shares is covered by the Registration Statement on Form S- 3ASR (File No. 333-284812) filed by the Company with the Securities and Exchange Commission (the “Commission”) on February 11, 2025 (the registration statement at the time it automatically became effective, including the documents or portions thereof incorporated by reference therein, as modified or superseded as described therein, and the information deemed to be a part thereof pursuant to Rule 430B under the Securities Act of 1933, as amended (the “Securities Act”), the “Registration Statement”) under the Securities Act, including the prospectus dated February 11, 2025 included therein (the “Base Prospectus”) as supplemented by the final prospectus supplement dated December 10, 2025, filed with the Commission pursuant to Rule 424(b) under the Securities Act (the “Prospectus Supplement” and, collectively with the Base Prospectus, the “Prospectus”). This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement or related Prospectus, other than as expressly stated herein with respect to the issue of the Shares. As to matters of fact relevant to the opinions rendered herein, we have examined such documents, certificates and other instruments which we have deemed necessary or advisable, including a certificate addressed to us and dated the date hereof executed by the Company (the “Opinion Certificate”). We have not undertaken any independent investigation to verify the accuracy of any such information, representations or warranties or to determine the existence or absence of any fact, and no inference as to our knowledge of the existence or absence of any fact should be drawn from our representation of the Company or the rendering of the opinions set forth below. We have not considered parol evidence in connection with any of the agreements or instruments reviewed by us in connection with this letter. In our examination of documents for purposes of this letter, we have assumed, and express no opinion as to, the genuineness and authenticity of all signatures on original documents, the authenticity and completeness of all documents submitted to us as originals, that each document

Archer Aviation Inc. December 10, 2025 Page 2 is what it purports to be, the conformity to originals of all documents submitted to us as copies or facsimile copies, the absence of any termination, modification or waiver of or amendment to any document reviewed by us (other than as has been disclosed to us), the legal competence or capacity of all persons or entities (other than the Company) executing the same and (other than the Company) the due authorization, execution and delivery of all documents by each party thereto. We have also assumed the conformity of the documents filed with the Commission via the Electronic Data Gathering, Analysis and Retrieval System (“EDGAR”), except for required EDGAR formatting changes, to physical copies submitted for our examination. The opinions in this letter are limited to the existing General Corporation Law of the State of Delaware now in effect (the “Applicable Laws”). We express no opinion with respect to any other laws. We express no opinion regarding the effectiveness of any waiver or stay, extension or of unknown future rights. Further, we express no opinion regarding the effect of provisions relating to indemnification, exculpation or contribution to the extent such provisions may be held unenforceable as contrary to federal or state securities laws or public policy. Based upon the foregoing, and subject to the qualifications and exceptions contained herein, we are of the opinion that the Shares are validly issued, fully paid and nonassessable. We consent to the use of this opinion as an exhibit to the Current Report on Form 8-K to be filed by the Company with the Commission in connection with the offering of the Shares and further consent to all references to us, if any, in the Registration Statement, the Prospectus and any amendments thereto. In giving this consent we do not thereby admit that we come within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission thereunder. [Concluding Paragraph Follows on Next Page]

Archer Aviation Inc. December 10, 2025 Page 3 This opinion is intended solely for use in connection with the resale of the Shares subject to the Registration Statement and is not to be relied upon for any other purpose. In providing this letter, we are opining only as to the specific legal issues expressly set forth above, and no opinion shall be inferred as to any other matter or matters. This opinion is rendered on, and speaks only as of, the date of this letter first written above, is based solely on our understanding of facts in existence as of such date after the aforementioned examination and does not address any potential changes in facts, circumstance or law that may occur after the date of this opinion letter. We assume no obligation to advise you of any fact, circumstance, event or change in the law or the facts that may hereafter be brought to our attention, whether or not such occurrence would affect or modify any of the opinions expressed herein. Very truly yours, /s/ Fenwick & West LLP____________ FENWICK & WEST LLP

exhibit_991

Archer Completes First Phase of Transactions To Acquire Control Of Hawthorne Airport Archer’s Midnight aircraft at Hawthorne Airport Hawthorne, CA - December 9, 2025 - Today, Archer Aviation (NYSE: ACHR) announced that it has now completed the first phase of its Hawthorne Airport transactions that includes the acquisition of the master lease from the City of Hawthorne and the associated subleases, giving it control of the real estate that makes up the airport. In early November, Archer signed a series of definitive agreements to acquire control of this one-of-a-kind Los Angeles aviation asset. Archer expects for the airport to serve as its operational hub for its planned L.A. air taxi network operations, including serving a key role in the LA28 Olympic & Paralympic Games. Furthermore, the airport is a profitable enterprise, which Archer believes has significant additional upside that has yet to be realized. The Hawthorne Airport is strategically located less than three miles from LAX, and is the closest airport to some of the city’s biggest attractions: SoFi Stadium, The Forum, Intuit Dome and Downtown L.A. Adam Goldstein, Archer’s Founder and Chief Executive Officer, said, “This is an important milestone as we look to build out the future of air taxis right here in LA. We are helping our great

cities rethink and redefine transportation as we prepare for the next phase of modernization and growth in our country.” The airport is located in the heart of L.A., sits on an 80-acre site and includes approximately 190,000 square feet of terminal, office and hangar facilities. The historic Hawthorne Airport was built in the 1920s and once helped shape Southern California's aerospace legacy and is also known as Jack Northrop Field. Archer also plans to utilize the airport as an innovation testbed for the next-generation AI-powered aviation technologies that it is developing and planning to deploy with its airline and technology partners. This includes AI-powered air traffic and ground operations management, in addition to other key technologies. With this evolution, Archer expects it can significantly enhance the upside for the already-profitable Hawthorne enterprise. Subsequently, Archer plans to acquire the airport’s FBO and passenger terminal next year in the second phase of the transaction, giving Archer full control of the airport and its day-to-day operations. About Archer Archer is designing and developing the key enabling technologies and aircraft necessary to power the future of aviation. To learn more, visit www.archer.com. Source: Archer​ Text: ArcherIR Forward-Looking Statements This press release contains forward-looking statements regarding Archer’s future business plans, expectations, and opportunities. These statements include those regarding design and target specifications of its aircraft, the expansion of its planned lines of business and development of new business opportunities, such as operating Hawthorne Airport and using it as a testbed for next-generation AI-powered aviation technologies; revenue potential and anticipated benefits of its planned operations at Hawthorne Airport; and plans and anticipated benefits of acquisitions, strategic investments, and collaborations with third parties. These forward-looking statements are only predictions and may differ materially from actual results due to a variety of factors. The risks and uncertainties that could cause actual results to differ from the results predicted are more fully detailed in Archer’s filings with the Securities and Exchange Commission (“SEC”), including its most recent Annual Report on Form 10-K which is available on its investor relations website at investors.archer.com and on the SEC website at www.sec.gov. In addition, please note that any forward-looking statements contained herein are based on assumptions that Archer believes to be reasonable as of the date of this press release. Archer undertakes no obligation to update these statements as a result of new information or future events. Archer Media Contacts​ The Brand Amp - archer@thebrandamp.com Source: Archer Aviation​ Text: ArcherIR