Leonardo da Vinci designed an ornithopter by studying the flapping flight of birds and bats.
An ornithopter is an aircraft intended to fly by flapping wings rather than by using propellers or jet engines. Leonardo filled notebooks with observations of birds, bats, and the mechanics of flight. His proposed machines included a frame, large wings, and pedals or levers for a pilot to operate the wings.
The designs were important as investigations into lift, balance, and wing movement, but they were not practical aircraft. Human muscles cannot normally provide enough sustained power to flap wings of the necessary size, and Leonardo’s mechanisms did not solve that engineering problem.
An ornithopter differs from a glider, which flies with fixed wings, and from a helicopter, which uses rotating blades. Modern experimental ornithopters have flown, but Leonardo’s machines remained concepts rather than proven inventions.