ST doesn't have carriers because fighters are uncommon and bombers are unheard of, for a variety of good reasons. There are a few exceptions, like Jem'hadar "fighters" (which are basically equivalent to a smaller Bird of Prey in terms of crew and armament, but actually seem to serve as troop transports?), runabouts, or the Delta Flyer. That size of ship is also roughly equivalent to the Jedi ships, both in terms of travel range and capacity for violence.