Exhibit 16.1

September 22, 2021

Securities and Exchange Commission

100 F Street, N.E.

Washington, DC 20549

Commissioners:

We have read the statements made by Archer Aviation Inc. (formerly Atlas Crest Investment Corp.) under Item 4.01 of its Form 8-K dated September 16, 2021. We agree with the statements concerning our Firm in such Form 8-K; we are not in a position to agree or disagree with other statements of Atlas Crest Investment Corp. contained therein.

Very truly yours,

/s/ Marcum llp

Marcum llp