The Rustler is a WWII fighter plane in Grand Theft Auto: San Andreas, apparently based on the North American P-51 Mustang (Wings, canopy, fuselage) with features derived from the Curtis P-40 Warhawk (empennage, propeller, air scoop) from WWII. It is the oldest aircraft in the GTA series.
It is fast and has very good manoeuvrability, as expected from a WWII piston engined fighter. It has 6 machine guns in the wings. It can also withstand a lot of punishment. Though the Rustler is seen flying around the skies, it makes no attempt to attack the player. Thus, the gun is hard to neautralize enemies airborne, because it has to go straight and discharge its machine gun to eliminate enemies.
It is used for most of the missions at the flying school, and for missions with Mike Toreno. It is found in one of the open hangars at Easter Bay International Airport or at the Verdant Meadows airfield.