The drone, with its Boeing 737 wingspan, will provide internet access to the most remote parts of the world. It will be tested in the United States later this year.
Weighing 400 kg the drone will hover between 60,000 feet and 90,000 feet above the altitude of commercial airplanes and ignore the weather.
Facebook said the drone, which was built in 14 months can fly for 90 days. Helium balloons will be attached to the plane and float it up into the air.
The planes will circle a three-km (two-mile) radius. During the day, they will float up to 90,000 feet (30 km) and at night will drift down to 60,000 feet (20 km) to conserve energy.
Facebook is not planning to sell the drones but will use them to expand internet access.
Facebook is the first company to fly at such altitudes. It has a team lobbying politicians to let it through… er to set guidelines.