re: Skipping Over the Atmosphere on a Surfboard
I don't know if such a thing is possible, but they might be intending to activate the ion engine at high altitude, and then deploy a surfboard-wing (solar sail perhaps) that would add lift as the speed increased. Gradually deflating the airship might also decrease drag. Speed might eventually become hypersonic. However I think heating of the aerosurfaces would be a serious problem. But imagine the airship gradually "morphing" into the Hyper-X, and then raising itself into an ever-higher orbit.
Like I said, I don't know if such a thing is possible.