Nuisance AI planes

I'm working on the London City airport, adding models made by our talented Australians. I was just going to test fly a Dash 8 by one of the talented Australians and the buildings in the background are by courtesy of the other one :-)Anyway, the purpose of this post is to focus on the AI planes. They taxi out on the runway and just sit there. Finally I got bored and overtook them to take off and that was when the first one started moving. Yes, I can taxi into position and hold / line up and wait but I can't sit there waiting forever. It may seem that the AI planes get stuck whenever there's a (player's) plane approaching it from behind. I know a little about FLED by now but I don't understand AI aircraft. How do they tick?best regards,Hans Petterhttp://forums.avsim.com/user_files/15945.jpg