Interior View of the Aircraft Building, South Yard, by Unknown, 1950s, Smithsonian Archives - History Div, A Lincoln Ellsworth's Northrop Gramma "Polar Star" and a Curtiss R 3C-2 racer, in foreground, exhibited in the Aircraft Building located in the South Yard as part of the National Air Museum, now the National Air and Space Museum. There is also exhibit cases with models of airplanes and part of airplanes..