Aviation themed RPG's are few and far between. I've tried to run a few, and a couple of others have come up, but they always die out really quickly. I'm desperately eager for more Ace-Combat-style games, which blend some sci-fi, larger than life elements into a somewhat military setting. 

Definitely agree with the sentiment about sci-fi themed RPGs as well. Especially space-opera style sci-fi. There's a smattering of post-apocalypse games and cyberpunk games - most likely due to the impending release of the video game - but honest-to-goodness space opera, either hard-SF or more Trek/Mass Effect/Halo/Star Wars/Battlestar Galactica style SF doesn't really come up as much. Probably because it requires a fair amount of world-building.