https://en.wikipedia.org/wiki/The_Menace_from_Earth https://en.wikipedia.org/wiki/The_Menace_from_Earth I'm not sure how realistic the muscle-powered flight is

https://en.wikipedia.org/wiki/The_Menace_from_Earth https://en.wikipedia.org/wiki/The_Menace_from_Earth I'm not sure how realistic the muscle-powered flight is, but a different form has been done on Earth.