AltEnergy Acquisition Corp. Unit Watch

from 8-K 30 pages Warrant Agreement

from S-1/A 30 pages Warrant Agreement

from S-1/A 5 pages [Face] Number Warrants This Warrant Shall Be Void if Not Exercised Prior to the Expiration of the Exercise Period Provided for in the Warrant Agreement Described Below AltEnergy Acquisition Corporation Incorporated Under the Laws of the State of Delaware Cusip [•] Warrant Certificate

from S-1/A 3 pages See Reverse for Certain Definitions AltEnergy Acquisition Corp. Incorporated Under the Laws of the State of Delaware Class a Common Stock This Certifies That Is the Owner of Fully Paid and Non-Assessable Shares of the Par Value of $0.0001 Each of the Class a Common Stock of AltEnergy Acquisition Corporation (The “Company”) Transferable on the Books of the Company in Person or by Duly Authorized Attorney Upon Surrender of This Certificate Properly Endorsed. the Company Will Be Forced to Redeem All of Its Shares of Class a Common Stock if It Does Not Complete a Business Combination by the Date Set Forth in the Company’s Amended and Restated Certificate of Incorporation, as the Same May Be Amended From Time to Time, All as More Fully Described in the Company’s Final Prospectus Dated , 2021. This Certificate Is Not Valid Unless Countersigned by the Transfer Agent and Registered by the Registrar. Witness the Facsimile Seal of the Company and the Facsimile Signatures of Its Duly Authorized Officers. [Corporate Seal] Delaware

from S-1/A 3 pages See Reverse for Certain Definitions AltEnergy Acquisition Corp. Units Consisting of One Share of Class a Common Stock and One- Half of One Warrant, Each Whole Warrant Entitling the Holder to Purchase One Share of Class a Common Stock