An airplane that never needs to land might sound impossible, but it is closer to reality now that a small solar-powered plane completed a two-day flight fueled only by energy from the sun. Dubbed the "SoLong," the craft built by the AC Propulsion company stores solar energy in a lithium-ion battery pack during the day to keep it flying at night.

"Many efforts, some extremely well-funded, have tried to find the balance that will keep a solar-powered airplane plane in the air for two consecutive nights. Until today, not one had found it." - Alan Cocconi, the solar plane's creator and chief pilot