Air tower
In addition to the standard features found in all Towers, the Air Tower is equipped with two Phalanx Wall Turrets on the roof walkway, greatly increasing their tactical value, and providing reasonably robust defence against infantry or vehicular assault.
The Air Tower is further equipped with two Landing Pads on the top of the roof, allowing Aircraft to quickly repair and rearm without having to go back to a Friendly Facility. The Phalanx Wall Turrets and the repairing/rearming Air Cavalry units make the Air Tower that hardest Tower to capture but it is also the most valuable of the three.
(Note: While a Facility expends NTU to auto-repair Wall Turrets, an Air Tower is considered to have infinite NTU for this purpose, although the rate is still very slow.)