Better alternatives
While this is cool, to me this seems much less promising than other technologies. Consider this:
http://www.solarairship.net
They also have a flying prototype. And their craft is faster, flies higher, is safer, wouldn't be affected by cloud cover, and most importantly can actually carry a useful load. I think the future of solar powered aircraft is more likely to take a shape like this than a heavy aircraft that can not lift anything.
Biting the hand that feeds IT
