Facebook filed a patent for an unusual drone that would use kites to stay aloft. The “dual-kite aerial vehicle” is composed of two kites tethered together and floating at different altitudes. Each kite could be directed independently, and the drone could generate its own energy to extend its flight time. As with all patents, we don’t know whether Facebook is building this system. But it indicates a continuing interest in experimental aerial vehicles, even after Facebook scaled back its earlier, well-publicized Aquila project.

Facebook’s patent was filed in November of 2018. It claims the kite drone would improve on more plane- or helicopter-like designs by cutting down the weight, cost, and size required to keep an aircraft flying for long periods of time — though they could still be fairly large, since Facebook mentions a kilometer-long tether. Fleets of drones could be operated wirelessly from the ground, and the drones could generate power through solar panels or tether movement.

This design has little in common with Facebook’s known drone prototypes, although it may have the same purpose: boosting or providing internet service in hard-to-reach areas. The Aquila, which it tested with mixed results in 2016, was a 900-pound winged aircraft made of carbon fiber. A lower-profile experimental program called Catalina reportedly used low-altitude bird-sized drones. This looks more like the balloons that Google’s parent company Alphabet has used for its Loon connectivity program.

Facebook seemingly got out of the drone design business last summer, saying that it would continue the Aquila project with hardware from established aviation companies. This patent application was filed roughly five months after that announcement. It includes claims that cover providing internet access with the kite drone.

Again, this doesn’t mean Facebook is building this drone, or that it’s actually a better design than more traditional options. And Facebook’s attempts to spread internet access worldwide have proven controversial — so even if the design is great, it may not want to launch a fleet of Facebook kites. But given that it’s previously partnered with companies like Airbus, it’s also not hard to imagine the company collaborating on new aerial systems.