The 1946 Ryan XF2R Dark Shark combined a nose turboprop with a tail turbojet. It flew well — but the all-jet age had already arrived.

Japan’s one-off Kawasaki Ki-64 hid two engines in tandem driving contra-rotating props, and cooled itself through its wings — until a fire ended it.

In 1977, Soviet test pilot Alexandr Fedotov zoom-climbed a MiG-25 to 123,523 feet — an absolute jet altitude record that still stands today.