I'm averaging like 5 kills per mission but have gotten no medals or promotions. I have been playing on medium difficulty, using autopilot and time skip to and from the objective, does that have anything to do with it?

Hi, medals and promotions also depends on SCORE POINTS using the Difficulty and Realism features of the game and always land your plane and turn off the engine on ground so it will ask you to end the mission and just press "Y" so it will give you more score points.

Also in game main menu go to "CONFIGURE GAME" and check if you are using in "DIFFICULTY" all FLIGHT realism on. Also check in "COMBAT" if you are using the max difficulty "ACE"

When you start a Campaign use CARRER DIFFICULTY "HARD" and maybe the other options like CARRER LENGTH, LIMITED AIRCRAFT and LIMITED SUPLY can also give you more score points I don't know ;)