That you by default remain at the field where you land is a given I think, don’t have a clue why it isn’t that way now..
About field captures of the ‘rear’ fields and closing them, I’m not sure you should be able to close or capture those fields, I don’t think they should be made natural targets. You should always be able to fly from them, but they should be affected by strat targets for fuel and so on. If they could be closed, think F1 with a rebuild time of five minutes or so for the hangars.
What I would like to see is a more pronounced front line, with many small forward fighter fields and vehicle depots, with some larger fields for bomber ops mixed in. Once an attack is pushed to where the front is in effective range of a rear field, the defenders will have a huge advantage, but I see that as a Good Thing <tm>. Winning the war could be a matter of pushing a country back to only the rear fields and then leveling all the strat targets.
I don’t like to see one country that is gang-banged and pushed back to a corner, even if it is badly outnumbered, and that would and should be extremely hard to do with a setup like this.
About the time to the fight problems, I would like a to see a separate training and fur ball arena where one could pop in for a quick fix. But that’s an other idea…
-Jinx