Large antennas, custom parts for Aquila drones. Aquila, a solar powered, 1,000 pound aircraft with a wingspan longer than a 737, had a first test flight on June 28. Huge engineering problems need to be solved before a fleet of Aquilas provide backhaul for rural cell towers. They are spending $tens of millions into advanced wireless research, building gear to test the state of the art. Aquila is no longer intended to serve people broadband. Instead, Facebook has the far more realistic plan of providing backhaul in extreme rural areas where fiber and terrestrial microwave would be too expensive.
Mark Zuckerberg and his top team are deeply committed to connecting everyone, a mutual friend tells me. Their Internet.org was inappropriate but their engineering is at the forefront. A 96 antenna massive MIMO rig delivered ten times the performance of typical LTE today. Their 60 GHz wireless mesh Terragraph prototype demonstrates how neighborhoods can be connected at multi-gigabit speeds. 60 GHz WiGig is likely to explode as Intel and Qualcomm are including it in new wireless chips and offering "Tri-band" local networking. The chart at right, from ABI, shows the trend coming in WiGig. The lighter blue sector in the upper right is WiGig. This chart is from 2013. The major growth is happening in 2017 and 2018, two years later than expected. (Wi-Gig deserves a long article if I ever get the time to write it.)
Facebook is "open-sourcing" most of their wireless findings rather than looking to earn a direct return.