Leonardo da Vinci designed an ornithopter, a flying machine intended to imitate the flapping wings of birds.
The word ornithopter comes from Greek roots meaning “bird” and “wing.” Leonardo filled notebooks with observations of birds, bats, and the mechanics of flight. His proposed machines generally used a human operator’s arms or legs to move large wings, rather than relying on an engine.
No Leonardo ornithopter is known to have flown. A human does not have enough power to flap wings of the required size, and the machine’s structure would also have been difficult to control. Even so, Leonardo’s studies correctly treated flight as a problem involving lift, balance, drag, and power.
An ornithopter is not the same as a glider. A glider uses fixed wings and remains aloft by moving through air, while an ornithopter produces thrust through flapping motion. Modern experimental ornithopters use motors or other mechanisms.