The BBS nickname is obvious. It's been a standard since before Air Warrior.
The "SaVaGe" thing came about because I'm about 1/2 Cherokee and 1/2 German. Through several games, from Dungeons and Dragons in the seventies, through Air Warrior in the nineties, I always had some sort of variation or part of "Renegade Savage" (as in wild Indian) for a nickname of sorts. However, several people in AW and AH have often assumed the "SaVaGe" comes from the character "General Frank Savage", played by Gregory Peck, in the movie "Twelve O'Clock High". But it does not.