Solar Impulse 2, the single-seater solar airplane unveiled today. Courtesy Solar Impulse The world’s most advanced solar plane, the Solar Impulse 2, was unveiled in Payerne, Switzerland, today. The plane, which has been in development for 10 years, is the successor to a solar plane that flew across the U.S. last summer. The plan is for Solar Impulse 2 to fly around the world next year using nothing but sunlight for power — the first solar-powered plane to accomplish that feat.