Simple...make a no ground strafing rule except to kill ground vehicles. In a Cyclone or Nox? Fair game. on foot, not a legit target. Whichever side wins the air war needs to either concentrate on vehicles (not landed and powered down ships), or land and join the FPS combat.If you use fighters, then one team always will win due to dogfight capabilities. Once won, they have space / air superiority, no decent FPS afterwards I did it before with CFT.
I made a compromise. First do the dogfight part, after the fight regroup and do the FPS part. This way everybody gets a share of their preferred action.
It requires a good location, where people can regroup fast, because the waiting part kills fun for everybody.
It forces a choice...send up fighters to try and bring down ships and maybe take out a critical troop transport, or meet them with your full force on foot. Do you put 5 people in that ursa, or have everyone walk?
Maybe put a timer on the game...at the end of the time, the ship can power up engines and shields and lift off. (ending the game unless there is someone on the ship). Again, it forces a choice for the aggressors on how close they want to land and how much time they want to spend creeping on on you, or waiting for the ballista to be destroyed.
EDIT - fighter pilots need to go into a big ship or the base to change into armor. otherwise all pilots need to be in flight suits only.