As far as I can tell when manipulating the levels of this image it looks to me that the man walking from left to right in the middle is not hovering but that his boots, a darker color then his pants are just blending in. With enough tweaking you can just barely make this out.
With that said. The holocaust happened and you have to wonder what point there would be in the altercation. I am not saying it couldn't have been doctored but if it was I don't think the appearance of the "floating man" is the proof that seals the deal.
If you are not one who can see the boot of the floating man another ting to look at would be the fact that he seemed to be moving quite fast as he is blurred much more then the others, so possibly you are seeing him with his knee bent will almost jogging to the right. It would have been nice to see a bigger version.
Just my 2 cents.