A solar-powered plane that has delighted aviation fans in Europe is preparing to fly across North America. The Swiss creators of the Solar Impulse plan to announce today which U.S. cities the experimental plane will visit during its Across America tour that kicks off in May.
 
The Solar Impulse is powered by about 12,000 photovoltaic cells that cover its massive wings and allow it to fly day and night without jet fuel. It has the wing span of a commercial airplane but the weight of a family car, making it vulnerable to bad weather.   Solar Impulse is planning an around-the-world flight in 2015.