Without forced team-balance you have no chance to balance the numbers on public servers, visited by more than 20 players randomly.
I don´t mind unbalanced teams generally if the missions are designed well.
Strafing as result of unbalanced teams is a typical syndrom of bored players. If you do not have any objective but to shoot at other other planes wich appear randomly and you do not find any plane to shoot at, you go for the place where you can be sure you find what you are looking for - the oppfor airfields.
So, give the players an objective, a feeling for the objective and an award for achieving this objective. At the same time penalize them for not achieving their objective and doing something stupid, like strafing enemy airfields with guns. This usually works to a certain degree. But so far on the DF servers you can simply leave your plane if it has a scratch on the canopy or you just put your plane and your v-life into the next hill, without any consequenzes - it too easy to follow the temptation of the quicky-airquake and besides you mostly have nothing else to do anyway. If you stop the AI Bombers or not, if bomb the train/ship/tank or not, so what? Teamplay? What for? Any formations you meet are usually AI bombers, no fighters, so...
Therefore you simply end up with the situation
of take-off, head to the next enemy airfield, if you do not find anything flying to shoot at, look on the ground, strafe a little, get shot down by the one above the airfield you didn´t see and repeat... 
So far I have seen, we only have this kind of dogfight servers, for CloD, maybe that will change someday...
sorry not time for a spell-check...