I feel a good emulation/simulation should model the usefulness of air units in WWII.
For power vs. IPC air units is a bad purchase.
By reducing the cost of the fighter the benefits of an air unit can show a tad better.
Yes sales is important at the end of the day.
Revised is for age 12+ so they can’t make it too complicated.
But for us, just create house rules to your tastes. Introducing air combat rules for example can add much dynamics to land combat.