Scientists from Microsoft Research have proposed using existing commercial aircraft flights and air routes to provide worldwide internet coverage at much lower cost than proposed solutions such as Google’s Project Loon (which uses balloons) and Facebook’s Aquila efforts (which uses solar-powered aircraft).
They propose using existing license-free WIFI spectrum and WIFI routers on commercial aircraft which already criss-cross the skies to communicate with repeaters on the ground, and believe they can offer at least some internet connectivity to 80% of the population of Africa at low cost and with existing technology.
They additionally propose to use the existing ADS-B signals from planes as a control channel to ensure that there is a strong link from the plane to the ground and that the stations intelligently wake up and associate to the appropriate AP.
Microsoft tested the system in real life and reports good performance. They note that connectivity would be intermittent and would be more suitable for latency-tolerant communication such as instant messages and email, but that connectivity can be improved by recruiting more flights (there are more than 10,000 in the air at one time) and by potentially rerouting flights slightly for better coverage.
With an estimated 3.8 billion people who do not have access to the internet, this solution appears to be low cost, novel, practical and achievable. The full paper can read here.