Leonardo da Vinci designed an ornithopter, a human-powered flying machine with wings modeled on a bat.
An ornithopter is an aircraft intended to fly by flapping wings rather than by using a propeller or fixed wings. Leonardo studied the anatomy and flight of birds and bats, then proposed mechanisms in which a pilot would move large wings through pedals, levers, and other controls. Several of his drawings show different arrangements, so there was not one single final Leonardo ornithopter.
The concept was scientifically insightful but probably could not have carried a human with Renaissance materials and muscle power. Human muscles do not provide enough sustained power for a machine of the necessary size, and the proposed mechanisms would have been difficult to operate. Leonardo also explored gliding and helicopter-like ideas, which are separate categories of flying-machine design. “Ornithopter” describes the flapping-wing principle, not a specific successful aircraft. Modern experimental ornithopters use engines, motors, or remote control, and a few small unmanned examples have flown, but Leonardo’s full-scale machine remained a design study.