This quarter Facebook reported a doubling in research and development spending from a year ago, as the company invests for the long term. Chief Technology Officer Mike Schroepfer sat down in an exclusive interview to talk about where Facebook is spending that money, and where it sees its future: Drones, artificial intelligence and virtual reality.

Facebook CEO Mark Zuckerberg says one of the company's greatest missions is to connect the world, including the 4 billion people who are not yet online. On Thursday Facebook's Connectivity Lab, which is focused on achieving that connectivity, announced a new milestone: Its drone designed to provide Internet service in remote areas is now complete and ready for flight testing. The aircraft, with the wingspan of a 737, but a weight hundreds of times less, is designed to circle for up to 90 days, "beaming connectivity down to people from an altitude of 60,000 to 90,000 feet."