This sounds like a pretty nifty project.
Having said that I'm all for this, I know less than nothing about scenery design. The whole ball of wax is a total mystery to me. Buildings, or other necessary library type objects, terrain mesh, you name it. I have dabbled a little in ADE, and that's as far as I've gone.
Some ideas I'd like to throw into the pot, if I may. Make it have very long, moderate size and very short runways. Put in a set of arrestor cables, on a moderate length runway, and a FLOLS light on it as well. Include a water runway. Include a short grass/gravel/coral/PSP type runway, or all of them on different runways, with different headings. Include a few Helicopter pad, maybe some elevated, some on trailers for pushing into a hangar, that sort of thing. Make some of the hangars have doors that open/close with a radio signal. Like keying the mic 3 times rapidly, on a specified frequency, or something like that. Same for some, or all, or the runway lights.
I am certain that many will have more, and probably better, ideas. I was just trying to throw in as much variety as possible for testing aircraft, gauges, and so on, against.
Anyway, sounds like a fun project, if nothing else. Thanks for the good idea!
Pat☺