1) keep current ma
2) add an arena,using custom terrains. it will cycle oncea week. flight operationswill be limited to planesthatfit the terrain,andwillbecountry-segregated.flight operations will be only enabled for 5 minutes every hour. If you die, go furball in MA and wait for next hour to roll on by.
this willkeep both arenas fairly active i think. much better than a normal historiocal arena since it will concentrate people and make more realistic environment. you could also disable radar and stuff in 2nd arena.