Leonardo da Vinci designed glider-like aircraft intended to descend through the air without powered flapping.
Leonardo investigated how a human could use broad wings to ride or descend on air currents. His studies included wing shapes, balance, control, and the behavior of birds in flight. Some designs resemble hang gliders more closely than powered aircraft because they rely on aerodynamic lift and forward motion rather than an engine or repeated wing beats.
A glider is an aircraft without an engine that remains airborne by using lift generated by its wings. It can descend gradually, and skilled pilots can use rising air to stay aloft or gain height. Leonardo’s drawings did not produce a verified successful human flight, but they anticipated important questions later addressed by aviation pioneers.
The term is narrower than “flying machine.” Leonardo also studied ornithopters, which were based on flapping wings, and screw-shaped aerial devices. Those concepts should not be treated as interchangeable with a glider.