I don't think there was enough critical mass in regards to pilots so they ended up shooting the available targets - GV's.
If there are sufficient anti-air gv's enabled then its more fair, imho, moreso if bombs are disabled.
I have no issues with the planes straffing, since they can't really hurt tanks.
But fundamentally, there weren't enough pilots/players to dilute the impact of planes as you hoped - not a reason to give up, tho'.