I would have thought that everybody should be able to co-exist peacefully, according to the 'happy hour model' which gets it spot on. I am not aircrew (although I do fit into the official description of who the forum is for), but I never post on the flying-only threads, I just wish there were more of them as they tend to me more entertaining than what goes past in between! Mind you, a lot of the more general threads make worthwhile contributions to the debate: for example, even the much-maligned MT rant throws a lot of light on a pretty wide cultural gulf that you obviously don't have to scratch the surface very hard to expose.
The aircrew purists could start more flying threads, and keep them going. As for a closed forum, how does anyone think that will work - a copy of your OJAR to prove who you are? More realistically there could be 2 forums, one for flying only and the other for general tenuously RAF related comment. If you moderated the backside out of the flying one to purge anything unworthy it could just work.
Keep Pprune united I say: 10 minutes on ARRSE is enough to remind me why I joined the Air Force; I can't understand a bloody thing they are saying on 'Rum Ration'; and the others are just full of Air Cadets. No offence, but that's not who I would drink with in happy hour. Where else can I go? (no suggestions please!)
JD