Leonardo da Vinci sketched an ornithopter, a flying machine intended to lift by flapping wings.
The word ornithopter means a machine that flies through the flapping motion of wings. Leonardo studied birds, bats, and human anatomy while developing several such concepts. His sketches often show a pilot lying or standing inside a framework and operating wings through levers, pedals, or other mechanical connections.
Leonardo never achieved powered human flight with an ornithopter. Human muscles cannot provide enough sustained power for a machine of the proposed size, and the materials and control systems available in the 15th and 16th centuries were inadequate. The designs therefore belong to the history of aviation concepts rather than successful aircraft.
The ornithopter is different from a glider, which relies on aerodynamic lift without flapping, and from a helicopter, which uses rotating blades. Leonardo's investigations nevertheless contributed to the study of lift, drag, balance, and wing structure that later aviation would develop through experiments and mathematics.