(CBS News) MOUNTAIN VIEW, Calif. -- The unusual aircraft called Solar Impulse sat on a California runway as its energy source rose in the east.
The plane has already flown over the Alps in Switzerland where it was built. It has even flown over Morocco at night on batteries recharged by the sun.
We took a close look with Sully Sullenberger, the retired pilot who safely landed a US Airways jet in the Hudson River.
"It's exciting to be so close to this fabulous machine," he tells Andre Borschberg, who designed and built Solar Impulse with fellow pilot Bertrand Piccard.
"It's exciting to meet you," Borschberg says.
"When we meet you before a flight, maybe we need the life jackets," Piccard jokes.
The aircraft has the same wingspan as a 747 but a cockpit barely big enough for one person. It weighs only as much as a midsize car.
"We are sensitive to turbulence," Piccard says. "We have to fly in good weather. So, of course, it's not yet the possibility of carrying 200 passengers at the speed of sound, but you never know. It can come."
Its wings are covered with 12,000 solar cells. It cruises at only 30 miles an hour, though in a strong wind, it may stand still -- even fly backward.
"In the 20th century, the goal was to conquer the world -- conquer the planet, even go to the moon," Piccard says.
"Go faster, higher, farther," Sullenberger adds.
Watch: Solar-powered plane aims to fly around the world, below.
"Exactly," says Piccard. "Now we've seen that we can conquer everything, but I think we should now conquer the quality of life. And we have to do it in a clean way."
The test flight over San Francisco Bay lasted 16 hours -- long after the sun had set.
Asked why aviation has the power to inspire, Sullenberger says, "There's something special about being able to leave the earth and not being bound by it."
The Solar Impulse pilots, like Sully Sullenberger, have accomplished things in flight that seem impossible. Their hopes, like their aircraft, are not bound by the earth.