X-36

Aircraft designers routinely use scale models, and in the case of the X-36 Tailless Fighter Agility Research Aircraft, that's as big as it got.

The 19-foot-long, remotely piloted X-36, built by Boeing's Phantom Works, is a 28 percent scale model that was created to test theories about the maneuverability and survivability of planes that lack a tail structure. Two were built, and together they made 33 flights in 1997 and 1998, including a pair of flights featuring Air Force Research Lab software that used a neural net algorithm to compensate for (simulated) in-flight malfunctions or damage.