Concept Model of Interior for the New National Air Museum, by Hellmuth, Obata & Kassabaum, 1964, Smithsonian Archives - History Div, Early concept model of the main floor interior for a new National Air Museum (now known as the National Air and Space Museum), designed by Gyo Obata of Hellmuth, Obata & Kassabaum (HOK). Visible In this open top model of the first floor for a "Museum for the Space Age" are airplanes, rockets, people inside the museum as well as people and cars on the outside..