From the help file:
Air points = PlaneDamageScore + KillScore
PlaneDamageScore =
(DamagePointsScoredOnEnemiesTh isSortie * DeathMult) +
TotalTourPlaneDamageScoredOnE nemies
KillScore =
((AirKillsThisSortie * 1.0) + (AirAssistsThisSortie * 0.25) +
(GroundKillsThisSortie * 1.0) + (GroundAssistsThisSortie * 0.25) * DeathMult) +
TotalTourKillScore
Death Multipliers:
Landed 1.0
Discoed 0.25
Bailed 0.5
Ditched 0.75
Captured 0.4
Killed 0.25
Crashed 0.25