The FAA will allow UPS to expand an operation delivering medical supplies using drones in North Carolina, Transportation Secretary Elaine Chao said Tuesday, authorizing the company to operate a fleet of unmanned aircraft and send them beyond the line of sight of crew on the ground.

“This is a big step forward in safely integrating unmanned aircraft systems into our airspace,” Chao said in a statement.

UPS formed a subsidiary called Flight Forward in July and applied for authorization from federal aviation authorities to operate the drones. Tuesday’s certification as an “air carrier” will allow the company to build on work it has been doing to deliver blood and medical samples at a hospital campus in Raleigh.

Wing, which is owned by Google parent Alphabet, received a similar approval from the FAA in the spring and announced last month that it would begin a pilot program delivering consumer goods by drone with Walgreens and FedEx this fall. Wing says it will be able to deliver packages within minutes of customers placing an order, hauling them on multi-rotor unmanned aircraft.

Officials and the industry see in drones the potential to revolutionize deliveries to remote areas, speed up shipments of lifesaving medical supplies and create new kinds of business opportunities. But the development of rules to allow the aircraft to fly safely alongside manned planes and helicopters has been slow, and some communities under potential drone flight paths have voiced concerns about privacy and noise.

The FAA has been running test sites like the one UPS has been working on in North Carolina to give operators and their partners a chance to test the technology and work out any hiccups. The FAA said in a statement that the approval it was giving UPS was based on “extensive data and documentation, as well as test flights” that showed the company could meet safety standards.

In July, Scott Price, UPS’s chief transformation and strategy officer, called its application for carrier status “historic.”

“UPS is committed to using technology to transform the way we do business,” he said then.

Technology companies and existing delivery businesses are experimenting with sending packages with drones, and at least half a dozen companies say they’re planning to seek approval as “air carriers.”