I believe the air maps will just result in the server being abandoned. Those that fly - I mean really like to fly - are using peripherals (i.e. joysticks) made for flying. It just doesn't work well with keyboard/mouse. These maps are made for the players that sit at the spawn screen on "normal" maps waiting to jump into an aircraft and they represent a very small minority of regular players.
For those unfamiliar with the air maps, I made a video (used a wired XBOX360 controller) from the CTE.
There are two modes that I know of: 1) Attacking / defending airship behemoths, and 2) TDM with airplanes.