I've been thinking along these lines:
All fighters have a 4+ save against other AC, representing the chance it has of surviving an engagement with enough fuel and ammunition to remain effective. Fighters that eliminate their opposition and pass their save may continue on to attack other targets. All fighters involved in a combat attack at once, but only bombers/assault boats that are directly attacked may fight back. Resilient Fighters gain a 3+ save. Other Resilient Ordnance gains a 4+ save.
How this will work:
Eg1: 2 fighters intercept 3 fighters. Each fighter makes 1 attack, so the intercepting fighters have to make 3 saves, and the defenders make 2. Any survivors then attack again until one side or other are dead.
Eg2: 3 Fighta Bommerz intercept 1 Starfury Fighter and 3 Starhawks Bombers.
The Starfury is attacked 3 times, and rolls 4,6,6, passing all its saves and survives. The 3 Fighta Bommerz are attacked once by the Starfury and roll a 2, so one of them dies. As both sides have survived, another round of combat is fought:
The Starfury is attacked 2 times by the surviving Fighta Bommerz, and rolls 3,3, and is destroyed. The additional failed save doesn't carry over onto the bombers. The Fighta Bommerz roll a 5, and so are fine. There are still markers on each side, so the fight continues, but as the escort is dead, the Starhawk Bombers are now attacked.
2 Starhawks are removed, as bombers have no save. The 2 Fighta Bommerz roll 3,5, leaving one Fighta Bommer. Both sides still have markers, so a fourth round is fought:
The last starhawk is removed as it has no save. The last fighta bommer rolls a 4, and so survives and may continue to move and attack a different target.