This is the Zephyr S, a solar-powered autonomous drone built by Airbus.
The Zephyr S has a wingspan of 25 meters and is designed to operate in the stratosphere, at an average altitude of 21km.
Uses for the Zephyr S include surveillance and reconnaissance, or providing internet access to remote regions.
Eventually Airbus wants the drone to fly for 100 days without landing, powered by its solar array. Airbus has opened a production line for the drone in Farnborough.