(Bloomberg) -- The government’s authority to overseeburgeoning recreational drone use was dealt a setback when afederal appeals court barred the Federal Aviation Administration from forcinghobbyists to register some of the millions of unmanned aircrafttaking flight.

While Friday’s decision by the U.S. Court of Appeals in Washington left intact FAAguidance on restrictions over where recreational drones may fly,the ruling undercuts one of the agency’s primary means of ensuringthat unmanned aircraft are operated safely. About 745,000 hobbyistshave signed up since the FAA regulation was enacted in 2015. Theagency estimates that 2.3 million drones will be sold this year forrecreational use, plus 2.5 million for commercial operations.

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Acting as his own lawyer, drone hobbyist John Taylor sued,contending the FAA didn’t have that power.

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

Drone registration was prompted by reports ofthe unmanned craft flying near traditionalaircraft, 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 inholiday sales.

Contrary to the mandate, though, was the FAA Modernization andReform Act, passed by Congress in 2012 and signed by formerPresident Barack Obama. The measure expressly barred the FAA fromissuing rules governing model aircraft use, according to the courtruling.

The FAA is reviewing the ruling, it said in an emailedstatement. “The FAA put registration and operational regulations inplace to ensure that drones are operated in a way that is safe anddoes not pose security and privacy threats,” the agency said. “Weare in the process of considering our options and response to thedecision.”

‘Innovative approach’

The ruling doesn’t apply to the growing number of commercial droneoperators, such as real estate photographers and cell-towerinspectors. It also won’t effect the plans of companies such asAmazon.com Inc. and Alphabet Inc. to create fleets of deliverydrones.

The world’s largest drone manufacturer, China-based SZ DJITechnology Co., said that the FAA’s registration system had madesense.

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“The FAA’s innovative approach to drone registration was veryreasonable, and registration provides for accountability andeducation to drone pilots,” Brendan Schulman, DJI’s vice presidentof policy and legal affairs, said in an email. “I expect the legalissue that impedes this program will be addressed by cooperativework between the industry and policy makers.”

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

‘Blatantly unlawful’

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

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

The FAA uses its regulation system to give users safetyinformation. The agency requires drones have identifying markingsso it can know which users pose a hazard risk.

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In its legal arguments, the FAA said that the same statuteTaylor cited also granted it authority to regulate unmanneddevices. The 2012 legislation, which was Congress’ first attempt atsetting policy for drones, said the devices were “aircraft,” whichthe agency interpreted as allowing it to set legally bindingstandards on their operation.

“The number of unmanned aircraft has increased rapidly, creatingsignificant concerns about the safety of the national airspacesystem, as well as the safety of persons and property on theground,” the FAA argued in a 2016 brief in the case. “This isespecially true given that many, if not most, owners of unmannedaircraft have no prior aviation experience and lack anunderstanding of the requirements for safe operation of theirunmanned aircraft.”

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

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