Archer Aviation Inc.

Rule 10b5-1 Trading Plans. During the three months ended June 30, 2026, none of our directors or officers adopted, modified orterminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement”, in each case as defined in Item 408 of Regulation S-K, except as described below.

On May 22, 2026, Eric Lentell, Chief Strategy & Legal Officer of the Company, adopted a trading arrangement intended to satisfy the affirmative defense of Rule 10b5-1(c), which expires on August 18, 2027 and provides for the sale of up to 90,000 shares of Class A common stock pursuant to the terms of the plan.

On May 21, 2026, Benjamin Lyon, President of Aircraft OEM of the Company, adopted a trading arrangement intended to satisfy the affirmative defense of Rule 10b5-1(c), which expires on June 25, 2027 and provides for the sale of up to 328,100 shares of Class A common stock pursuant to the terms of the plan.

Update On Relationship with Stellantis

The Company and Stellantis N.V. and its subsidiaries (together, “Stellantis”) have agreed to supersede the collaboration framework previously contemplated under the November 2024 Memorandum of Understanding (the “MOU”), as disclosed on a Current Report on Form 8-K filed on November 4, 2024. On August 9, 2026, the Company and Stellantis entered into several definitive agreements setting forth the terms under which Stellantis will continue to provide certain manufacturing support resources to the Company for a specified period of time. In consideration of Stellantis providing those services since February 2025, the parties agreed to, among other things: (i) the termination of each party’s obligations under the subscription agreement they entered into in December 2024; (ii) the issuance by the Company of a warrant to Stellantis for 1,539,154 shares of the Company’s Class A common stock at an exercise price of $0.01 per share (the “Warrant”), which are fully vested and will expire on the fifth anniversary of the warrant issuance date; and (iii) the extension of the lock-up restriction that applies to the shares of the Company’s common stock held by Stellantis and its affiliates, through the earlier of: (x) the third trading day following the filing of the Company’s Annual Report on Form 10-K for the fiscal year ending December 31, 2026, (y) March 31, 2027, and (z) the first date on which Stellantis and all of its affiliates are no longer required to file a Schedule 13D or Schedule 13G (or any amendment thereto) with the SEC.

The foregoing description of the Warrant does not purport to be complete and is qualified in its entirety by the full text of the form of Warrant, a copy of which is filed herewith as Exhibit 4.1.

Scheduled Public Warrants Expiration

The Company's outstanding public warrants (NYSE: ACHR WS), each exercisable for one share of the Company's Class A common stock at an exercise price of $11.50 per share, are scheduled to expire at 5:00 p.m., New York City time, on September 16, 2026, in accordance with the terms of the warrant agreement, dated October 27, 2020, between the Company (as successor to Atlas Crest Investment Corp.) and Continental Stock Transfer & Trust Company, as warrant agent (incorporated by reference to Exhibit 4.1 to Atlas Crest Investment Corp.’s Current Report on Form 8-K filed with the SEC on November 2, 2020). As of June 30, 2026, there were approximately 25.4 million shares of Class A common stock issuable upon exercise of the Company's outstanding public and private warrants, with an exercise price of $11.50 per share. Any public warrants not exercised prior to their expiration will thereafter be void and of no further force or effect.