What Leonardo da Vinci design imitated bird wings with a flapping mechanism?

Leonardo da Vinci’s ornithopter was a flying-machine design that imitated birds by using flapping wings.

Leonardo studied birds and their wing movements while developing several flying-machine concepts. His ornithopter sketches placed a human pilot inside or beneath a lightweight framework, with mechanical parts intended to move large wings. The pilot’s arms, legs, or both would have supplied some of the movement through pedals and levers.

The design was never proven capable of sustained human flight. Human muscles cannot generate enough power to flap wings large enough to lift a person, which is why modern aircraft use engines and fixed wings or powered rotors. The ornithopter remains important because it shows Leonardo’s approach: observing nature closely, then translating biological motion into mechanical systems.