It's not hard to levetate a short amount off of the ground, or at least give the illusion that you're doing so. There's a trick to it that would be hard to explain here so try to find a video about how to do it, it's really simple and obvious once you know how it works.

Now, if he was like a foot off the ground, I can't explain that with anything other than possible camera tricks or set-up of some sort.