My suggestion would be to assign certain aircraft to certain hangars, example: hangar #2 at small field, P-51's, Spit 9 and 10, P-47-D25's and so forth. So if a player wanted to limit the "Ponies" around, just kill hangar #2 at all small fields!
great first people are killing hq all the time. Now limit me from flying my favorite airplane. Give me another reason to quit. semp
Do not get caught up in the country-centric thinking.
Air warrior had a spit factory. Kill that, and you couldn't up a spitfire for like 15 minutes. Personally, if they clustered some plane factories n here, but not having stupid long downtimes, I think this would be a fun strategic target.