Before thousands of drones hit the skies to make widespread package delivery a reality, there’s going to have to be some kind of air traffic control system to make sure drones can fly autonomously without colliding into each other.

On June 6, the team from Project Wing — the experimental drone delivery project at Alphabet’s X “moonshot” umbrella organization — tested a new system to manage drone traffic, Recode reports.

Taking part in tests convened by NASA and the U.S. Federal Aviation Administration, Project Wing conducted trials of its own drone traffic control platform at Virginia Tech, where the FAA has set up a test site for flying drones. Wing discussed the project in a blog post published on June 7.

The problem of tracking and managing drone flights will be critical to figure out before drone delivery can come to fruition. Drones don’t take off and land from the same place on set routes — in the way airplanes use airports — but rather are supposed to work more like cars, going direct to and from homes and offices. Operators will need to know where other drones are flying in order to prevent collisions, as well as which areas to avoid and when, like if there’s a major sports event or a wildfire.

There is no comprehensive nationwide U.S. system for tracking drone traffic, which is one reason why it’s not legal for drones to fly beyond the line of sight of the operator.

In Project Wing’s test, the team was able to track the flight paths of multiple drones at once on a single platform. Three of the drones were Project Wing’s own aircraft, a winged drone that the company hopes will one day be used to deliver food and retail items. Another drone in the test was made and operated by Intel and a third drone was an Inspire from DJI. Those two were simulating search and rescue operations, while Wing’s three drones were testing delivery scenarios.

With Wing’s drone air traffic control system, the drones automatically steered away from each other without an operator needing to pilot the drones to manually avoid collision. The software helps drones plan routes and sends information to aircraft when an airspace restriction is issued.

Wing isn’t the only company exploring low-altitude air traffic control solutions with NASA and the FAA. Airmap — a company that makes a platform to alert air traffic controllers and drone operators to where drones are flying and is already in use at nearly every major airport across the country — is also working with the federal agencies, as are Amazon, Uber and GoPro.

Project Wing completed a burrito delivery with Chipotle to Virginia Tech students last September at the same test site it conducted its recent traffic management trials.

Still, the last year at Wing hasn’t been without turbulence.

A former employee told the Wall Street Journal in a report from last December that the latest model of the Wing drone at that point hadn’t been able to complete more than 300 successful flights before something went wrong.

And in the final quarter of last year, the CEO of Wing, David Vos, as well as Sean Mullaney, Wing’s top commercial executive at the time, left the company.

NASA and the FAA aren’t scheduled to be done with their research into how to integrate drone air traffic control into the national airspace until 2019. But that doesn’t necessarily mean drone delivery will have to wait that long.

On Monday, June 5, Donald Trump shared a proposal to privatize the federal air traffic control system, and last week, Transportation Secretary Elaine Chao laid out plans for a pilot program to let local communities experiment with different approaches for controlling drone activity in their airspace.

Both may open the doors for private companies to contract with the government to provide drone air traffic control solutions, as opposed to, say, the FAA building its own system, which could take a lot longer.

And that means that drone delivery in U.S. skies could happen sooner than previously anticipated, Recode said.