[omegaman]

http://www.wired.com/autopia/2012/08...di-hover-bike/

[LCARS 24]

Well, that raised some technical questions, but this covers the broad strokes:

http://4wings.com.phtemp.com/tip/tpdduct.html

So using the ducts as a major portion of the craft's structure, the shape of the ducts, and minimum clearance between the tips of the blades and the ducts are important in designing a hovercraft that doesn't kick up a lot of dust, which means the ducts and other structural members have to be extraordinarily rigid in relation to their weight. Sounds like carbon fiber and maybe some triangulated tubes.

Still, that's a lot of work for the engineers to get it right, and a lot of faith on the part of the guy bankrolling the project.