The Solar Impulse:
http://www.npr.org/blogs/alltechconsidered/2013/03/27/175371800/solar-powered-plane-uses-its-lightness-to-fly-in-the-dark

Next month, a very odd looking plane will take off from Moffett
Field in Mountain View, Calif., and head east to New York. The Solar Impulse —
the world's first solar-powered plane — is capable of flying nonstop all day and
all night. Its creators plan to fly it across the U.S. this spring, and by 2015
they hope to fly a similar aircraft around the world.

Its wingspan is longer than a 747 Boeing, but the entire plane weighs less than
a car.

"That was the challenge," says Andre Borschberg, one of the creators and a
pilot. He says the wings are so large in part to generate lift and in part to
create a bigger surface "to integrate solar cells."

Ah, not the first solar powered plane.