Flight simulators play an essential role in maintaining the exceptional level of safety that commercial airlines offer the traveling public. Modern flight simulators are available for all types of commercial aircraft, with mock cockpits that include functional analogs of every control in the real cockpit, and simulator time is an required component of every airline transport pilot's training.

Flight simulators developed from the obvious desire to provide a training environment for student pilots that did not necessitate actually being in a plane. Early airline pilot training, in the 1940s, did require the use of actual planes, which was both expensive and provided a less-than-ideal practice environment.

The simplest type of simulator is a cockpit procedure trainer, which is simply a replica of the cockpit of a particular type of plane, in which a student can be taught the location and use of the instruments and controls...