The Baade 152
The German-built plane was made with the idea to be a bomber plane. It would have been amazing as a bomber plane but not as a normal aircraft. The test plane crashed and everyone on board died. It was canceled in 1961 and remains the only plane created by East Germany.
The Rockwell XFV-12
Creating the first airplane aircraft ever is a hard task, but it’s expected that by the 1970s designers would be skilled enough to create a plane that would not go so terribly. Unfortunately, this idea was not quite on point. It had great features but it never made it in the air.