From The Vault
Hellion is a powerful, heavily-armed aircraft, located in Buena Vista. It is a prototype weapon which wasn't finished before the war, so it's completion is one of the objectives given to Calculator after the activation of it's pacification
protocol. Calculator was meant to ensure the safety of inhabitants of Vault 0 and secure the region of all the mutants and possible foreign soldiers. To do so, it required something beside the army of robots, so the Hellion was placed in Buena Vista with a working nuclear reactor, waiting for the day the Calculator will start its protocols. Many years later,
the Calculator emerged as a major threat to humanity, an became the main enemy of Midwestern Brotherhood of Steel. It is unknown whether the Hellion was in a working condition, as Calculator may have already abandoned it for some reason, for example the lack of resourses to use it. With the destruction of nuclear reactor, the Calculator lost its chance to use the craft, and the Brotherhood surprisingly ignored its existence, likely due to the war with the robots.
[edit] Appearances in games
Hellion appear only in Fallout Tactics.
