A Swiss solar-powered plane has taken off for its first international flight. The Solar Impulse team behind the project plans to fly the experimental aircraft to Belgium and France. The single-seater prototype took off from Payerne airfield in Switzerland at 8:40 a.m. (0640 GMT) Friday and is expected to reach Brussels airport by nightfall. The plane with the wingspan of a Boeing 777 made its 2009 maiden flight in Switzerland and further tests have all taken place there. The flight across France, Luxembourg and Belgium poses a fresh challenge as it requires navigation across international air traffic networks.