I started as Ghost51. Couldn't come up with a good unique name so I went with "Ghost" because I thought I'd attack people so fast that they would think a ghost killed them, and "51" because I was a brainwashed teen who had been told the P-51 was the "best" fighter of WW2.
Stuck with Ghost for a few tours, added squad number to it, etc.
Banshee7 came about when I had become considered one of the most hated squeakers in the game. Got caught in the wrong crowd and stuff. "Banshee" came from three things--1.) I used to ride a friends Yamaha Banshee all the time. 2.) The P-51B named "Beantown Banshee" 3.) It sounded cool. The "7" came along because of the overused 'lucky #7"