On Thanksgiving weekend of 2013, Jeff Bezos, then Amazon’s CEO, took to 60 Minutes to make a stunning announcement: Amazon was a few years away from deploying drones that would deliver packages to homes in less than 30 minutes.  It lent urgency to a problem that Parimal Kopardekar, director of the NASA Aeronautics Research Institute, had begun thinking about earlier that year. “How do you manage and accommodate large-scale drone operations without overloading the air traffic control system?” Kopardekar, who goes by PK, recalls wondering. Busy managing all airplane takeoffs and landings, air traffic controllers clearly wouldn’t have the capacity to oversee the fleets of package-delivering drones Amazon was promising.  The solution PK devised, which subsequently grew into a collaboration between federal agencies, researchers, and industry, is a system called unmanned-­aircraft-system traffic management, or UTM. Instead of verbally communicating with air traffic controllers, drone operators using UTM share their intended flight paths with each other via a cloud-based network. This highly scalable approach may finally open the skies to a host of commercial drone applications that have yet to materialize. Amazon Prime Air launched in 2022 but was put on hold after crashes at a testing facility, for example. On any given day, only 8,500 or so unmanned aircraft fly in US airspace, the vast majority of which are used for recreational purposes rather than for services like search and rescue missions, real estate inspections, video surveillance, or farmland surveys.  One obstacle to wider use has been concern over possible midair drone-to-drone collisions. (Drones are typically restricted to airspace below 400 feet and their access to airports is limited, which significantly lowers the risk of drone-airplane collisions.) Under Federal Aviation Administration regulations, drones generally cannot fly beyond an operator’s visual line of sight, limiting flights to about a third of a mile. This prevents most collisions but also most use cases, such as delivering medication to a patient’s doorstep or dispatching a police drone to an active crime scene so first responders can better prepare before arriving. Now, though, drone operators are increasingly incorporating UTM into their flights. The system uses path planning algorithms, like those that run in Google Maps, to chart a course that considers not only weather and obstacles like buildings and trees but the flight paths of nearby drones. It’ll automatically reroute a flight before takeoff if another drone has reserved the same volume of airspace at the same time, making the new flight trajectory visible to subsequent pilots. Drones can then fly autonomously to and from their destination, and no air traffic controller is required.  Over the past decade, NASA and industry have demonstrated to the FAA through a series of tests that drones can safely maneuver around each other by adhering to UTM. And last summer, the agency gave the go-ahead for multiple drone delivery companies using UTM to begin flying simultaneously in the same airspace above Dallas—a first in US aviation history. Drone operators without in-house UTM capabilities have also begun licensing UTM services from FAA-approved third-party providers. UTM only works if all participants abide by the same rules and agree to share data, and it’s enabled a level of collaboration unusual for companies competing to gain a foothold in a young, hot field, notes Peter Sachs, head of airspace integration strategy at Zipline, a drone delivery company based in South San Francisco that’s approved to use UTM.  “We all agree that we need to collaborate on the practical, behind-the-scenes nuts and bolts to make sure that this preflight deconfliction for drones works really well,” Sachs says. (“Strategic deconfliction” is the technical term for processes that minimize drone-drone collisions.) Zipline and the drone delivery companies Wing, Flytrex, and DroneUp all operate in the Dallas area and are racing to expand to more cities, yet they disclose where they’re flying to one another in the interest of keeping the airspace conflict-free. Greater adoption of UTM may be on the way. The FAA is expected to soon release a new rule called Part 108 that may allow operators to fly beyond visual line of sight if, among other requirements, they have some UTM capability, eliminating the need for the difficult-­to-obtain waiver the agency currently requires for these flights. To safely manage this additional drone traffic, drone companies will have to continue working together to keep their aircraft out of each other’s way.  Yaakov Zinberg is a writer based in Cambridge, Massachusetts.