Leonardo da Vinci designed an ornithopter, an aircraft concept with wings intended to imitate a bird’s flapping motion.
Leonardo studied birds extensively and produced several flying-machine sketches based on flapping wings. His ornithopter concepts used frames, wing surfaces, and systems of levers or pedals that a pilot might operate. The goal was to reproduce the lifting and propulsive action of a bird rather than to use a propeller or a rotating rotor.
These designs were important studies in biomechanics, but they were not practical human-powered aircraft. A human pilot lacks the power-to-weight ratio needed to flap wings of the necessary size and force. Leonardo’s drawings therefore belong to the history of flight ideas, not to a record of successful aviation.
The ornithopter is distinct from Leonardo’s aerial screw. The aerial screw uses a rotating helical surface for vertical lift, whereas an ornithopter depends on repeated wing strokes. Modern ornithopters exist mainly as small experimental or model aircraft.