Facebook has completed the first successful test flight of Aquila – the high-altitude, long-endurance solar plane that will one day beam internet to parts of the world that are not yet connected.
Facebook is already used by over a billion people on Earth - more than any other social network on the planet.
But the company has ambitious plans to expand the availability of the internet through a series of autonomous drones circling high up in the sky.
The thinking behind it is that the drones can beam a WiFi signal to areas of the globe that (for geographical or economic reasons) aren't served by a cell tower.
It means that more people around the world will be able to get online and communicate with each other - preferably through Facebook, although the company says that's not the only goal.
Aquila, named after the eagle in Greek mythology that carried Jupiter's thunderbolts, is based on technology developed by British company Ascenta, which Facebook bought in March 2014 for an estimated £12.5 million.
Ascenta has been absorbed into Facebook's Connectivity Lab, which is working on new aerospace and communications technologies, and also includes experts from Nasa.
Aquila is designed to be hyper efficient, so it can beam internet signal to people within a 60-mile communications diameter for up to 90 days at a time.
It has the wingspan of a Boeing 737, but at cruising speed will consume only 5,000 watts - the same amount as three hair dryers, or a high-end microwave.
When complete, Aquila will be able to circle a region up to 60 miles in diameter, beaming connectivity down from an altitude of between 60,000 and 90,000 feet using lasers.
Facebook has been flying a one-fifth scale version of Aquila for several months, but this was the first time it has flown the full-scale aircraft.
The test flight, which was designed to verify Aquila's operational models and overall aircraft design, was conducted at an altitude of 2,000 feet and lasted for more than 90 minutes.
"We were able to verify several performance models and components, including aerodynamics, batteries, control systems, and crew training," said Jay Parikh, global head of engineering and infrastructure at Facebook.
"In our next tests, we will fly Aquila faster, higher and longer, eventually taking it above 60,000 feet. Each test will help us learn and move faster toward our goal."
While the successful test flight of Aquila is a major milestone, Facebook admitted it still has a lot of work ahead of it.
In order to reach its goal of being able to fly over a remote region and deliver connectivity for up to three months at time, it will need to break the world record for solar-powered unmanned flight, which currently stands at two weeks.
"This will require significant advancements in science and engineering to achieve," said Parikh.
"It will also require us to work closely with operators, governments and other partners to deploy these aircraft in the regions where they’ll be most effective."