Hang gliding is an air sport in which a pilot flies a light and unmotorized foot-launchable aircraft called a hang glider (also known as Delta plane or Deltaplane). Most modern hang gliders are made of an aluminium alloy or composite-framed fabric wing. The pilot is ensconced in a harness suspended from the airframe, and exercises control by shifting body weight in opposition to a control frame, but other devices, including modern aircraft flight control systems, may be used. In the sport's early days, pilots were restricted to gliding down small hills on low-performance hang gliders. However, modern technology gives pilots the ability to soar for hours, gain thousands of feet of altitude in thermal updrafts, perform aerobatics, and glide cross-country for hundreds of miles. The Fédération Aéronautique Internationale and national airspace governing organizations control some aspects of hang gliding. Gaining the safety benefits from being instructed is highly recommended.