“Taylor does not think that the FAA had the statutory authority to issue the registration rule and require him to register,” U.S. Circuit Judge Brett Kavanaugh wrote for the unanimous three-judge panel. “Taylor is right.”

Drone registration was prompted by reports of the unmanned craft flying near traditional aircraft, including airliners at some of the largest U.S. airports. The registration system went into effect Dec. 21, 2015, as officials hurried to set it up before an expected spike in holiday sales.

Contrary to the mandate, though, was the FAA Modernization and Reform Act, passed by Congress in 2012 and signed by former President Barack Obama. The measure expressly barred the FAA from issuing rules governing model aircraft use, according to the court ruling.

The FAA is reviewing the ruling, it said in an emailed statement. “The FAA put registration and operational regulations in place to ensure that drones are operated in a way that is safe and does not pose security and privacy threats,” the agency said. “We are in the process of considering our options and response to the decision.”

‘Innovative approach’

The ruling doesn’t apply to the growing number of commercial drone operators, such as real estate photographers and cell-tower inspectors. It also won’t effect the plans of companies such as Amazon.com Inc. and Alphabet Inc. to create fleets of delivery drones.

The world’s largest drone manufacturer, China-based SZ DJI Technology Co., said that the FAA’s registration system had made sense.

Related: Terror risk from small domestic drones has U.S. officials worried

“The FAA’s innovative approach to drone registration was very reasonable, and registration provides for accountability and education to drone pilots,” Brendan Schulman, DJI’s vice president of policy and legal affairs, said in an email. “I expect the legal issue that impedes this program will be addressed by cooperative work between the industry and policy makers.”

Taylor, a lawyer from Silver Spring, Maryland, filed the case within days of the formation of the registration system.

‘Blatantly unlawful’

“The registration regulation was so blatantly unlawful,” Taylor said in a phone interview. “I was in disbelief that the FAA would attempt it. So I was pleased to see the court see it that way.”

While he filed the case himself, Taylor said he had the assistance of several attorneys who specialize in aviation law. When asked how many unmanned aircraft he owns, he replied “a bunch,” saying it was difficult to count them all. He has some commonly available off-the-shelf models as well as ones he’s built himself, he said.

The FAA uses its regulation system to give users safety information. The agency requires drones have identifying markings so it can know which users pose a hazard risk.

Related: If you invade someone's privacy with a drone, your insurance might not cover it

In its legal arguments, the FAA said that the same statute Taylor cited also granted it authority to regulate unmanned devices. The 2012 legislation, which was Congress’ first attempt at setting policy for drones, said the devices were “aircraft,” which the agency interpreted as allowing it to set legally binding standards on their operation.

“The number of unmanned aircraft has increased rapidly, creating significant concerns about the safety of the national airspace system, as well as the safety of persons and property on the ground,” the FAA argued in a 2016 brief in the case. “This is especially true given that many, if not most, owners of unmanned aircraft have no prior aviation experience and lack an understanding of the requirements for safe operation of their unmanned aircraft.”

The case is Taylor v. Huerta, 15-1495, U.S. Court of Appeals, District of Columbia (Washington).

Copyright 2018 Bloomberg. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.