This article examines the institutional and commemorative politics of artifact selection during the development of the Smithsonian National Air and Space Museum (NASM) for the United States Bicentennial. Although museum staff i ntroduced formal criteria for artifact selection, decisions about exhibition objects remained the subject of negotiation among curators, government agencies, veterans’ organizations, and political actors. Through two controversies surrounding the Navy NC-4 and the DH-4 Old 249, the article explores two contrasting forms of negotiation over aviation heritage. The NC-4 case examines how the Smithsonian and the U.S. Navy negotiated the institutional representation of naval aviation within the nation’s official aerospace museum. By contrast, the DH-4 Old 249 controversy reveals tensions between professional standards of historical authenticity and the commemorative claims advanced by former air mail personnel and their political supporters. By shifting attention from completed exhibitions to the contested process of exhibition planning, this study demonstrates that aviation heritage was shaped not simply through curatorial judgment but through negotiations over historical authority, institutional representation, and collective memory during the making of a national museum.