Oh, it's definately real. It's not a plastic lawnmower, it's a kit that's designed to LOOK like a lawnmower, but it's lightweight and has aerodynamic surfaces, some of which are not immediately evident.
It, like the F-117, is a testament to the fact that you can get just about anything to fly with the proper C/G and enough power. I've seen a flying football and an R/C witch on a broomstick.