The Whatsit was a swept-wing, tail-less airplane designed by Waldo Waterman between 1911 (when he first got the idea) and 1932 (when the prototype was finally in testing phase). Waterman completed the prototype with friend and fellow engineer, Max B. Harlow. It was intended to be an aircraft which could be landed on the street, and owned by regular people. The original Whatsit was donated by Waterman himself in 1950 to the Smithsonian Institution's National Air and Space Museum.