The ability to control an unpiloted aircraft from remote locations offers numerous advantages. With manned aircraft, you must accommodate not only the added weight of a pilot, but also the pilot's safety. In military conflicts, for instance, a plane, if detected, may be shot at by enemy anti-aircraft weaponry. Unmanned aerial vehicles (UAVs) can fly at higher altitudes over long periods than can piloted craft, and they can perform high-speed evasive maneuvers, the forces of which would stretch a person beyond his or her physical limitations. Freed of the weight of a pilot, UAVs can carry more communications and monitoring equipment. Computerized control systems can also maneuver airplanes more reliably than manual systems can in certain difficult phases of flight, such as low-level night flying over undulating terrain or bad-weather landings.
Early UAVs were typically converted airplanes. As mission goals evolved to include high-altitude and long-duration surveillance flights, weapons delivery, stealth capability, weather monitoring, rescue operations, changes in structural designs, fuel systems, and on-board technologies naturally followed. Today's planes are equipped with real-time communications capabilities, advanced imaging systems, television relays, and infrared cameras. Some non-military vehicles have begun to tap solar power and fuel cell storage systems. A class of mini-UAVs, called MAVs, has even been designed to mimic the flying movements of certain insects.