In one book (can't remember which), there were patrol boats and small squad-based inflatables used, but mainly by the PDF I think. But this was also based one a planet with lots of islands, and with a local population of tribesmen, so naval vessels would be necessary.
But on planets with proper navies, I'd guess that they'd mostly be like today's warships: mainly missile orientated. Aircraft carriers would mainly be support vessels, as missile craft make carriers obsolete, just as carriers make battleships obsolete.
