How does a pilot steer a plane through empty air?

A pilot steers a plane by tilting hinged surfaces on the wings and tail, which changes how the air pushes on each part. Three controls do the main work. The control yoke or stick governs roll and pitch: turning or pushing it left and right moves the ailerons, and moving it backward or forward moves the elevators. The rudder pedals control yaw by moving the rudder. Roll, pitch and yaw are the three ways a plane can turn about itself.

The ailerons are hinged pieces on the back edge of each wing, used in pairs. When one goes up and the other goes down, the plane rolls, and tilting the lift this way changes the plane's path. They took over from wing-warping, the Wright brothers' method of twisting the wings themselves, because they turned out to be much more effective and practical, and they did not weaken the wing. By 1911 most biplanes used them.

Ailerons have a side effect: rolling right produces a yawing motion to the left, called adverse yaw. The pilot cancels it with the rudder, which is how a coordinated turn is made.

The layout itself is more than a century old. The recognisable system appeared on Louis Blériot's monoplane in April 1908, and today's pilots still use the same pattern. It even led to a fight: the Wrights and Glenn Curtiss spent years in court over the Wrights' patent on controlling a plane's roll, and the Wrights won several decisions against Curtiss's ailerons.