I think his idea is related to those "spray gliders", which are in my mind a brilliant invention. They work by changing boyancy. When they are heavy, they dive downward using the wing to glide horizontally. When they get to a predetermined depth, they increase boyancy, making them lighter than water. They then glide up to the surface using their wing to make them move horizontally. All in all they can travel hundreds of miles using very very very little power.
Here's a link.
http://www.whoi.edu/instruments/viewIns ... do?id=1498
In any case, if the concept works in water, a similar concept should work in air.
Hmmm. Maybe Someday they'll swim with the Cetaceans on Europa.
Thanks, I like the machine!