I’ve toyed with this idea somewhat, but only in my head. If you want more realism, air power by itself should not be able to win land battles. It should be able to shift the odds, sometimes dramatically, but winning should require sizeable ground forces.
What would happen if all battles – land, air, sea – were limited to three rounds of combat? Maybe with a Blitzkrieg rule: If you wipe out the defending forces in one round, tanks and mechs can move and attack an additional territory, if they did not move two spaces to get to the initial battle. Any aircraft that participated in the initial attack could, if they had the remaining movement, participate in the first round of combat of the new battle. This would mean overall casualties during a turn would not be as high, which would require another rule to slow down production. Maybe double (or triple?) the cost of all units, and make the more expensive and powerful units take more than one turn to build. Infantry, subs, destroyers, AA guns, and transports can be built in one turn, like they are now. Tanks, mechs, artillery, fighters, tacs, cruisers, bombers, and minor ICs take two turns. Battleships, major ICs, and carriers – 3 turns.
Of course, it would be more complicated, require a lot of extra bookkeeping, and a typical game would take longer to play. And the joy of Axis & Allies is that you can play it while inebriated.