Suspicious travel companions: Bacteria can survive for days on surfaces inside a plane. But that doesn't mean you have to take these critters home with you. Benjamin Arthur for NPR hide caption

itoggle caption Benjamin Arthur for NPR

The Solar Impulse, a solar-powered plane, flies over Switzerland. The makers will be journeying across the U.S. this spring, hoping the flight helps challenge assumptions about what solar technology can do. Courtesy of Solar Impulse hide caption

itoggle caption Courtesy of Solar Impulse