Ominous Floating Spaceship: It’s certainly possible (see, for example, all the examples of how it’s done under Floating Continent).  It’s almost never done, however, because (a) putting all the equipment to make it hover, and the power budget to power said equipment into a combat spacecraft makes it a pretty crappy combat spacecraft for its class; because (b) making your expensive combat spacecraft hang in the air at point-blank range for the ground defenses and the orbital defense grid both, with limited ability to maneuver, is not generally considered a career-enhancing tactical move; and because (c), putting your expensive spacecraft anywhere where a power failure (probably the one that’s about to result from (b), actually) will cause it to fall out of the sky, destroying both itself and the also expensive real estate you were trying to acquire, is even less so.  Although at least you probably wouldn’t survive (c) to be court-martialed.