Maybe I was not clear enough or you didn't quite read it thoroughly. This thread is not about flight sims. It's about action/shooters where flight would be primary element instead of infantry but not to the exclusion of infantry, tanks, etc.
I think that I understand what you were-- and or are-- saying. If you wanted to have ground scale and air scale players on the same game, then you couldn't have the tempos match or you would have to totally forgo realism or the ability to play in realtime with others.
A game like Spore operates on multiple scales, and that works because the players on the sub scale are virtual. I guess that you could do something like that, with an army, navy, and airforce. Where in each part of play, the computer generates some fingerprint of your playing ability and scales it out for the next higher scale of play.