Wind tunnels are machines in which objects are held stationary inside a tube, and air is blown around it to study the interaction between the object and the moving air. They are used to test the aerodynamic effects of aircraft, rockets, cars, and buildings. Different wind tunnels range in size from less than a foot across, to over 100 feet (30 m), and can have air that moves at speeds from a light breeze to hypersonic velocities.

Karl Wilhelm Otto Lilienthal was a German pioneer of aviation who became known as the "flying man". He was the first person to make well-documented, repeated, successful flights with gliders, therefore making the idea of heavier-than-air aircraft a reality. Newspapers and magazines published photographs of Lilienthal gliding, favourably influencing public and scientific opinion about the possibility of flying machines becoming practical.