[Mark / Ohio]

Hover mowers have been around for years:

Flymo - Wikipedia, the free encyclopedia

I've saw several at shows but never saw one in use. From what I've read they has their pluses and minuses. Good on slopes and could be lowered with a rope easier then an electric wheeled mower. I think many had 2-cycle engines so you did not need to worry about oil starvation from being tipped too far to the side.

 

[Mark / Ohio]

Yeah, the down draft to float it would seem counter productive considering many mower designs tout their lifting and vacuuming ability. Likely would work best on short stiff bladed varieties of grass but I think their real nitch is mowing where you could only safely go with a string trimmer otherwise.