I dont think everyone gets the picture of the airplanes…
We waont use airplanes in EVERY map.
Just in maps that are capable of useing them!
Planes in Oasis? 
uhm NO
We use custom maps for this with a inventive idea on how to use them.
For diff maps, the admin can disable the Airborne Devision
(Each Devision can be closed or opened by a admin from map to map, same for the classes within, and same for the weapons within the classes)
And dont mind the walking distance…
The Pilots will spawn in a distance, but foot players just spwan near the action. We use some sort of teleports for the Pilots to fly thru big spaces.
(So first you start in the airfield, and you lift off, then you go thru a invisible teleport, and then you are in some big open sky box, after that you go thru another teleport and you are at the map where it all happens.
The enemy can also send planes to fight incoming planes of, so in the second (open sky) box dogfights could be possible)