Why leave it just at making all of the fuel tanks of equal size ? Why not make all aircraft have the same number of damage boxes and identical maneuver schedules ? At the same time, let all players have a consistant dice roll, it could still be randomized, but both players would have the same roll.
With the only difference in the aircraft being the colour scheme, it would eliminate all chance and qualitative differences and leave Blue Max to be a TRUE test of skill.