If Amazon and Google have their way and quadcopters become as commonplace as delivery vehicles, it could lead to some very busy skies. To manage this problem, a number of companies and institutions are working on air traffic control systems for drones — including Alphabet subsidiary Project Wing.

In a Medium post published yesterday, Project Wing’s co-lead James Burgess revealed that the company has deployed a prototype drone control system in a series of tests organized by NASA and the Federal Aviation Administration (FAA). The software uses a number of Google systems for support (Google Maps helped created “a detailed understanding of the world” and the company’s cloud service provide processing power) and was able to successfully manage “the complex flight paths of multiple UAS [unmanned aircraft systems] at the same time,” adjusting routes on the fly to avoid midair collisions.

“This is an important step that paves the way to a future where many UAS operators can fly safely together,” wrote Burgess. “It also makes it possible for a single operator — a person or organization — to fly multiple aircraft simultaneously.”

The company predicts that in a few years’ time, Wing and other firms will have fleets of drones numbering in their thousands. However, these initial tests were very limited in comparison — organizing an aerial ballet using just three Wing drones, two from Intel, and one from DJI. The Wing aircraft were tasked with picking up and delivering packages, while the other three were performing “automated search and rescue missions.”

Drone air traffic control is still in its infancy, and there’s a lot of work needed to be done before these systems will be robust enough to work with hundreds of aircraft. But this is a promising step forward — and could end up being a lucrative venture for Google itself.