Seeing unknown/strange things in the sky above a secret military test facility or air force base really doesn't seem that baffling or strange to me.
Why would someone want to shoot a particle accelerator into the sky? (The article mentions plasma balls, but as a non physicist I wonder still "Why?")
The US military probably does not want plasma balls because they look pretty.
http://www.otherhand.org/home-page/area-51-and-other-strange...
http://www.otherhand.org/home-page/area-51-and-other-strange...
The explanation is he worked on particle accelerators as a mechanic (not a physicist), and they were shooting particle beams into the sky. However since this is all likely classified he would be forced to stick to his UFO story.