@Mongoose: First, I don't know anything about coding. Second, I don't know anything about tactics. Yet, I believe I can answer your questions.
Why does it need to exist? Why not? It's got a function so it has to exist. I'd find it more strange and less immersible to be able to select vehicles in an invisible or non-existing place. It's not a Higgs boson or a Gravitational wave which have to exist based on calculations, but have been actually proved to exist only lately.
If it could be destroyed, there should be some other means to tell that some planes/vehicles aren't available, or that some resources such as bombs or fuel are restricted. It could as well be a grunt carrying a damage report. Or, like in the early text based games, simply a text message telling all that. However, there's much more information in clicking "Hangar" than in the clipboard right click "<field#> status" report that something just has to exist.
I suppose that if the detailed situation report of available resources is tied to a certain object on the field, it'd be easier to make sure every field has it.
Then again, all of the above may just be totally wrong. In that case, read the first two sentences again.
