Leonardo da Vinci’s bird-inspired flying-machine concept was an ornithopter.
An ornithopter is an aircraft designed to fly by flapping wings, rather than by using fixed wings or a rotor. Leonardo studied birds and bats extensively and filled notebooks with observations about lift, balance, wing movement, and air resistance. His designs generally imagined a human pilot producing motion through pedals, levers, or other mechanical linkages.
Leonardo’s ornithopter drawings were theoretical studies, not successful aircraft. Human muscles cannot provide the sustained power needed to flap a large winged machine carrying a person, and Leonardo did not have a lightweight engine. His work nevertheless anticipated the importance of controlling airflow and understanding the structure of wings.
The term should not be confused with “helicopter,” which uses rotating blades, or “glider,” which uses fixed wings and does not flap them. Leonardo also explored a separate screw-shaped aerial device, but that concept is not an ornithopter. His bird-flight studies helped make aviation a subject of systematic mechanical investigation centuries before powered flight.