Sounds like your problem is pretty severe so I don't know if these ideas will help, but here goes. Another old trick is to use a special bug trapping jar. Food is put inside and hung. The fly can fly (up) into the jar, but not (down to get) out of it. I have seen them around somewhere off base, I'm just not sure where. I will keep my eyes peeled and let you know where they are located when I see them again or you might want to do an online search or try it with an old plastic water bottle.
We bought an electric bug-zapping racket (looks a lot like a tennis racket) off base. Works great indoors as well when they decide to visit.
Where's those big lizard when you need them??