Sort of sounds like a plasma window - if there are charged particles "under" your ship, you can push on them with an electromagnetic field and they can push on whatever you're trying to repulse.
You couldn't thrust with it (well, I suppose you could, but then it's no different from a rocket) but maybe you could contain a gas "under" your ship like an air bearing.
However, I think it would have to powered with hand-wavium if you wanted to do anything more than break the last few feet of a decent.
Atomic Rockets is a pretty good resource for writers who want write realistic space fiction.
It's also pretty good at sucking away all free time for a few days.