Leonardo da Vinci’s ornithopter used a flapping wing inspired by birds for proposed human-powered flight.
Leonardo studied birds closely and designed several machines that imitated their wing movements. An ornithopter is an aircraft intended to fly by flapping wings, rather than by using a fixed wing, propeller, or rotor. His sketches explored frames, wing surfaces, cables, and foot- or hand-powered mechanisms that might produce the required motion.
Leonardo correctly recognized that bird flight involved more than simply moving wings up and down. He examined balance, air resistance, wing shape, and the relationship between body weight and available muscular force. Nevertheless, a human pilot could not generate enough power with Renaissance technology to sustain flight using his proposed machines.
The ornithopter is therefore a famous example of biomimicry and aerodynamic observation, not a successful aircraft. It is also distinct from Leonardo’s aerial screw: the ornithopter sought lift through flapping wings, while the aerial screw sought vertical lift through a rotating helical surface.