Suggestion:
Add logic to the AI controller such that if the targeted plane they are attacking has their velocity vector point back at the attacker, as the distance closes, based on closure rate, the attacker has a probabilistic chance of deciding break and avoid. The probability increases with closure rate and inversely to distance.
Reasoning:
It is very hard to make good missions where the two opposing flights just don't drill right into each other guns blazing and all 8 planes are tumbling burning wrecks after the first pass.
Quite spectacular, but not optimal unless you just enjoy fireworks displays. There are some judo contortions you can use to try and work around this, but it makes making missions harder than it should be and requires a lot of trial and error for anything other than simplistic cold merges.
Suggestion-b:
Add logic to the AI controller such that if the targeted plane they are attacking has their velocity vector point away from the attacker, as the distance closes, based on closure rate, the attacker has a probabilistic chance of throttling back to avoid ramming from the rear. The probability increases with closure rate and inversely to distance. At some danger close range, the attack maneuvers off instead of just throttling back.
Reasoning:
If you balance the AI perfectly so that it becomes a stalemate, where you can't shake them off your six, but they can't get a steady gun solution (fun!) they'll still climb up your six until they simply ram you from behind. (Not fun!)
$0.02,
CptTrips