I think this is a not so complex feature that would set you apart from everyone else.
Being able to hire/improve your fighter pilots. Even something as simple as two stats for fighter pilots, like "offence" and "defence" or Attack and Evasion would add a lot of flavour! Youd be able to track kills, transfer them between craft - maybe even have a mission to rescue a downed pilot; but that is a bit out of the way.
Anyways, it would be really cool adding that "human" element that all your soldiers have to the fighter pilots as well.