Transplanted from the general board:
Allow the C47 / M3 / Amphib to carry either 1 or 2 squads of troops (either 1 x 10 or 2 x 5). Squad-leaders can be player controlled. So an M3 can pull up outside a field and deploy two seperate groups of 5 men who will follow their human leader. They won't be auto-gunners, but the human player will be able to fire a small calibre gun.
You already have the graphic for troops, you already have a troop-model for player movement. You can use weapon-cycle to model rounds of magazine, and the code to delay weapon firing could be a base for later jam-modelling of gun temperatures.
Allow players to launch troops from fields with an intact barracks, make the "training" stat of the country affect the launch-rate of troops for a given player (or field?).
Incentives given to players:
. Ground vehicles at the field for anti-troop combat.
. Ground vehicle patrols to look out for sneaky troops trying to get into position.
. More association between pilots and drivers because they occasionally play troop themselves.
. Presence of lurking troops at a field might encourage bombers to occasionally carpet a field with a nice barrage.
It's not that far away from being feasible, unless you'd feel it neccessary to animate the troops from day 1 (I don't think you would), model head-bob (I think we could wait for that) or do other clever stuff.
. If the troops can re-board the M3 then players have a tactical withdrawl option for troops, and you have also implemented the feature that gives players SAR features =)
I think most of us would find a 'fire' button on the current chute/troop model awesome fun (a pistol only while you are in your chute?) Maybe in the version after you add this change the ground-graphic to have his gun poiting forwards.