An experimental solar-powered airplane embarked on its first transcontinental flight on Thursday, The Associated Press reported. The Solar Impulse plane left Switzerland and, after a pilot change in Spain, should reach North Africa next week. The aircraft features a 207-foot wingspan and more than 12,000 solar panels. The project began in 2003 and is estimated to cost about $100 million over 10 years. The Swiss traveled to Belgium and France last year to complete the Solar Impulse’s first international flight. The mission to Africa is described as the final dress rehearsal before a round-the-world flight that will include stops in the United States using a newer and more improved model scheduled to be unveiled in 2014.