Tonyspike, Keeping it in one thread is superb idea! I heartedly approve!
Don't worry about rambling -- I'm just the opposite (I don't get paid by the word. Actually, I don't get paid at all!! HEY!!!)
In SF2 you'll find a really unique feature - the userlist.ini. This can be applied (in some 3rd Party add ons) to ships, vehicles, various other ground objects, as well as the main "feature" - the aircraft. That, and the "Limited Nations" statements in the terrains main ini, and their attendant "Allowed Nations List" (aka "Nations.ini"), coupled with Exported = True/False (which ties back to the userlist) should -this being the operative word!- prevent the oddity you mention (Egyptian MiGs over Iceland). Now, so even more odd things can happen -- ever seen North Korean Meteors or Hunters?? The addition of another statement in the aircraft's data ini "Exported to Enemy = TRUE" adds a whole 'nuther lever of screw ups. But that's for another time.
The single missions you mention, are automatically generated when each mod folder is created. I don't think there's any way to get rid of them, as they exist in one of the missiondata cat files. You'll just have to ignore them.
That's how it works -- because all contents are stored in the same core object cats. It's just the way it is.
As to each and every plane showing up, yup, they sure do! IDF Scooters in your SF2:Europe, French Mirages in Viet nam, etc. BUT..like I said above, the userlist should prevent them from showing up in single missions, and most definately in campaigns. If they actually are an annoyance (like, "I don't even want to take the chance of them showing up,) just delete their folders. The same is true for GroundObjects. But, as all Red Side comes from the Soviet Union ... only a very few "nation specific" vehicles exist that could cause issues.
the folks that say that are morons.
If that was the case, how is it that I have 3 seperate WW2 installs (MTO, ETO, PTO, but not CBI as I haven't finished that terrain) and have no issues??
Trust to the people that have been playing, modding, and disassembling these games since 2003 (2005 on my part!).
any other questions, we'll try address on a case-by-case basis