I’d still like to see a few more aircraft types, mind.
Consider the present model as the early war reconnaissance type, fighting at 1-1. Successive types add greater firepower until you end up with a 4-4 fighter. Mainly this is restricted within air-to-air combat, so it doesn’t seriously imbalance the ground war. However surviving aircraft still get a single roll at their level vs ground. Don’t know yet if aircraft participate in naval battles.
Another approach here is to allow aircraft to level up with experience; that is for each kill in air vs air they move up one level to a maximum of 4 in combat value, including strafing vs ground units.
To facilitate this, you’d need to paint a fuselage number from 1-4 on each aircraft, changing a plane for the next number up if it wins a dogfight.
This depends, though, on the exact mechanics for air supremacy combat, and the number of aircraft pieces supplied.
For example, if air combat is a simple case of each plane rolling a die and hitting on a 1, then leveled up planes are likely to shoot each other out of the sky on a regular basis. But perhaps the dogfights are based on the best roll of a round winning the combat, with mutual destruction not possible.
If we only get, say, 4 aircraft per power, then the system would be rather difficult.
So I might need a supply of suitable scale WWI planes; and national roundel decals for this conflict would be a nice touch.