Its darn near impossible now to shoot down a plane in an anti-aircraft, even as an engineer. 5.5 or 7.5 seconds is simply not long enough, not by a long stretch to do any damage to a plane before he vanishes out of your sights to repair.
The top score in this match was made by the person being in an aircraft for 95% of the game. We could not shoot him down.
The nerf to engineers/anti-aircraft has completely over tuned airplanes.