The Thunderbolt Fighter is the Imperial Navy's primary heavy atmospheric fighter. Its nose armament will make a mess of anything in front of it, and its airframe is easily loaded with whatever payload a particular mission requires, like missiles (air-to-air and air-to-ground) or bombs, or even reconnaissance equipment. Though it looks about as aerodynamic and maneuverable as a flying brick (seriously, its wings are like slabs of metal), it apparently is capable of serving as an air superiority fighter, and its bulk brings survivability and ease of repair -- its pilot is actually capable of repairing damaged drive systems mid-flight!
It is equipped with a rocket in its tail in addition to its two jet engines; the rocket is not suitable for space combat, but rather used to launch from an orbiting mother-ship into the upper atmosphere (and vice versa), as well as take-offs from hydraulic "fast-launch" ramps (essentially aircraft-carrier catapults, but on the ground).
Introduced in the revamped Aeronautica Imperialis game, the Thunderbolt Fury replaces the quad autocannons in the nose with a pair of Avenger Bolt Cannons, the lethal minigun usually mounted on the Avenger attack craft. This allows it to shred enemy fighters like there is no tomorrow, but has a limited ammunition supply reducing its effectiveness in prolonged engagements. It should be asked how the fuck this makes sense, as the dedicated ground attack craft of the Navy, the Avenger itself, only carries one cannon and sacrifices a lot of space to do so. This little shit managed to get two.
The model was produced by Forge World, with rules first published in Imperial Armour Volume One - Imperial Guard and Imperial Navy, and periodically updated since (most recently in Imperial Armour Aeronautica).