The Uk is leading the world in the development of Hydrogen Fuel Cell’s for drones. Intelligent Energy, a UK start up company, has launched 4 products for commercial drones.
Recently their 800 watt Fuel Cell broke the Guinness World Record for the longest multi-rotor time. The drone, operated by South Korean Company Metavista, flew for over 12 hours smashing the previous record which was just over 2! More can be found about the company on their website.