Airplanes don't flap their wings and boats don't wag their tails.

Assuming that all technology should imitate nature is a naive engineering principle. The solution should solve the problem within the given constraints.

Nature came up with something much better in both those cases.

Portable, energy efficient, light, doesn't need refined oil, tightly steers...

Boats and aeroplanes are terrible in comparison. They only work due to a huge network of global effort.