TIE fighters are a class of small combat craft that are used by military and police forces, mercenaries, corporate security forces, and even criminal organizations like the United Pirate Clans. Unlike traditional Starfighters and other types of Airspeeders, TIE fighters lack gravity-control technology.
Rather, a TIE fighter relies on a solar-powered rocket engine for flying in both atmospheres and in outer space. Solar power is provided by a pair of large solar panels, and indeed TIE is short for "twin in on engine".
TIE fighters were first manufactured by the Astrotech Cartel for the New Shi'ar Imperium, but the technology was after adopted by other governments and spaceship builders, as TIE fighters proved to be cheaper to build than traditional starfighters based upon airspeeder tech.
TIE fighters lack Hyperdrive, and do depend on larger spaceships for traveling interstellar distances between solar systems.
TIE fighters are generally 15 to 20 feet long, the same size as starfighters and other airspeeders.