Exhibit 4.1 NPO NUMBER SHARES CA COMMON STOCK COMMON STOCK ADVANCED AERODYNAMICS & STRUCTURES, INC. INCORPORATED UNDER THE LAWS SEE REVERSE FOR OF THE STATE OF DELAWARE CERTAIN DEFINITIONS CUSIP 0075DB 10 7 This Certifies that is the record holder of FULLY PAID AND NONASSESSABLE SHARES OF CLASS A COMMON STOCK, $.0001 PAR VALUE PER SHARE OF ADVANCED AERODYNAMICS & STRUCTURES, INC. transferable on the books of the Corporation in person or by duly authorized attorney on surrender of this certificate properly endorsed. This certificate shall not be valid until countersigned and registered by the Transfer Agent and Registrar. WITNESS the facsimile seal of the Corporation and the signatures of its duly authorized officers. Dated: COUNTERSIGNED AND REGISTERED AMERICAN STOCK TRANSFER & TRUST COMPANY TRANSFER AGENT AND REGISTRAR BY AUTHORIZED SIGNATURE [signature] [signature] SECRETARY AND EXECUTIVE [SEAL] CHAIRMAN AND CHIEF EXECUTIVE VICE PRESIDENT OFFICER The Corporation shall furnish without charge to each stockholder who so requests a statement of the powers, designations, preferences and relative, participating, optional or other special rights of each class of stock of the Corporation or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights. Such requests shall be made to the Corporation's Secretary at the principal office of the Corporation. The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or regulations. TEN COM - as tenants in common UNIT GIFT MIN ACT - _________________Custodian________________ TEN ENT - as tenants by the entretles (Cust) (Minor) JT TEN - as joint tenants with right of under Uniform Gifts to Minors survivorship and not as a tenant Act___________________________________________ in common (State) UNIF TRF MIN ACT - _______________Custodian (until age________) (Cust) ___________________Under Uniform Transfers (Minor) to Minors Act________________________________ (State) Additional abbreviations may also be used though not in the above list. FOR VALUE RECEIVED____________________________________hereby sell, assign and transfer unto PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE _______________________________________________________________________________________________________________________ (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE _______________________________________________________________________________________________________________________ _______________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________Shares of the common stock represented by the within Certificate, and do hereby irrevocably constitute and appoint _______________________________________________________________________________________________________________Attorney to transfer the said stock on the books of the within named Corporation with full power of substitution in the premises Dated_______________________________ X ___________________________________________________ X ___________________________________________________ NOTICE: THE SIGNATURE(S) TO THIS ASSIGNMENT MUST CORRESPOND WITH THE NAME(S) AS WRITTEN UPON THIS FACE OF THE CERTIFICATE IN EVERY PARTICULAR, WITHOUT ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER SIGNATURE(S) GUARANTEED BY_________________________________________________________ THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTRUCTION, BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATION AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAMS. PURSUANT TO S.E.C. RULE 17ad-15 [LOGO]