Federal aviation officials say so many people are registering drones and applying for drone pilot licenses, they wonder if there will eventually be millions of drones crowding the nation’s skies.

Earl Lawrence is director of the Federal Aviation Administration. Lawrence told a government-industry committee Friday that 550,000 drones have been registered with the agency in the 9 months since the registration process was created. He says new registrations are coming in at a rate of 2,000 a day.

By comparison, the FAA says there are 260,165 manned aircraft registered in the U.S.

The FAA began issuing drone pilot licenses less than a month ago. Already, 13,710 people have applied to take the pilot exam, and 5,080 have passed it.

The FAA had previously forecast 1,343 drone pilots by 2020.