I like them inverted for ships/vehicles but not for first person cameras, if that makes any sense. Surely I'm not alone?

I think the difference here is that I think of the vehicles as being parallel to a horizontal plane whereas people are normally standing up so perpendicular. Hitting "up" means different things across those two scenarios.

Same for me. I need inverted controls for flight/space sims, but use direct controls for FPS games.