The secret project, codenamed SkyBender, is currently in a trial phase at Spaceport America in New Mexico, the Guardian reports . The plan could potentially offer data speeds around 40 times faster than the maximum 4G/LTE speeds currently available to smartphones and other devices.
For the purposes of testing the network, Google is renting out 15,000 square feet of hangar space and has set up a dedicated flight control centre, the report says. Eventually, the firm wants its solar-powered unmanned aerial vehicles to provide high-speed connectivity across the globe.
The idea is not too dissimilar to the Project Loon initiative Google has already talked about, but in this case drones act as the mobile hotspots rather than hot air balloons - it's also reminiscent of Facebook's own drone-powered internet network scheme.
Signals are beamed from a phone to a base station via the autonomous aircraft cruising in the sky. The new 5G network runs via millimetre-wave radio transmissions, which offer very high speeds but a much shorter range than 4G broadcasts, and can also be affected by bad weather. Sources say Google is experimenting with complex "phased array" technology to boost the range of its 5G drones.
There's no official comment from Google yet so it's not clear exactly when (or if) this drone-powered 5G network is going to be made public, but initiatives such as Project Fi show the company is determined to get as much of the world connected to high-speed internet as it can.