PS. I just looked at the design link. It sure doesn't look like it
would hover. I'd like to see it in action. I think you could construct
the whole body using light cardboard. I would scale it a bit larger and
use a lithium cell phone battery to power a hobby motor and prop. When
you cut out the actual lithium cell from the case you have a tiny,
lightweight power pack. The motor can be from some Chinese made toy at
the dollar store. Coupling from the motor shaft to the prop could be
plastic tube, vinyl or PVC.
I just received a circular from Harbor Freight where they sell a remote
controlled airplane for $5.99 on sale, regularly $13.99. That
drivetrain could be converted to a hovercraft.