Wikipedia
Bodyflight, or 'body flight', is the art of 'flying your body' in a controlled manner. This include turns, rolls, lateral movement, fall rate control, and other acrobatics in the air. The skill of bodyflight makes it possible for skydivers to fly closer to each other while they are falling, to allow them to link together in formation skydiving, then fly apart to a safe distance before opening parachutes. Many skills of bodyflight can be learned in a vertical wind tunnel, to enable skydivers to become better at controlling their bodies in the sky.
Bodyflight is accomplished via increasing/decreasing the drag of your body, using arms and legs as rudders for bodyflight motion control, as well as other techniques similar to that of an airplane. Professional athletes who fly through the air for long distances, such as ski jumping, have also used certain bodyflight techniques to increase jumping distance by manipulating their bodies to be more airfoil-like. Frequent visitors to a vertical wind tunnel are often called 'tunnel rats', much like frequent visitors to ski slopes are called 'ski bums'.
Some body flying enthusiasts develop their tunnel-flying skills not for sky diving training, but in order to be able to give professional performances. AERODIUM Latvia has a group of professional performers – air acrobats. The team started with a performance at the closing ceremony of the Winter Olympics 2006, and now performs in mobile and stationary vertical wind tunnels all around the world.