PAYERNE Switzerland, July 7 (Reuters) - A solar-powered aircraft designed to fly round the clock without traditional aviation fuel or polluting emissions headed on Wednesday into its crucial first night flight.
The plane, named Solar Impulse, took off for its first 24-hour test flight just after dawn from an air base near this central Swiss town and began climbing above nearby lakes and mountains toward a peak altitude of 8,500 meters (27,900 feet).
