Leonardo da Vinci designed an ornithopter to achieve flight with continuously flapping wings.
The term ornithopter describes a heavier-than-air aircraft propelled by flapping wings, imitating birds or bats. Leonardo studied bird anatomy, wing movement, and the mechanics of flight in several notebooks while developing human-powered flying-machine concepts.
His designs typically placed a pilot inside a framework connected to large wings. Some versions used the pilot's arms and legs to operate mechanisms, but human muscle power is insufficient to lift a person with the proposed arrangement. Leonardo also explored gliding and rotating-wing ideas, so not every flying-machine sketch was an ornithopter.
No Leonardo ornithopter is known to have flown. His work remains important because it linked observation of animal flight with mechanical analysis, even though the materials, power source, and aerodynamic understanding available in the Renaissance could not produce a practical aircraft.