WASHINGTON – The number of pilotless drones potentially flying in U.S. airspace has eclipsed the number of piloted aircraft — from Cessnas to Dreamliners, the Federal Aviation Administration said Monday.

More than 325,000 people registered their drones as of Friday, surpassing the 320,000 piloted aircraft registered with the FAA, Administrator Michael Huerta told a drone conference at K&L Gates law firm.

The number of remote-controlled aircraft is even greater because each registrant uses the same number for all of their drones, Huerta said. The average operator has 1.5 drones, he said.

The FAA began the registration program on Dec. 21 as part of an educational effort to instruct operators about the rules that apply to recreational drones. The Know Before You Fly program provides brochures about flying no higher than 400 feet within sight of the operator during daylight hours and not near an airport.

“We’re very encouraged by the registration numbers we’ve seen so far,” Huerta said. “Safety is at the heart of this new registration system. We need to bring the unmanned aircraft enthusiasts into the culture that has characterized aviation throughout its history – that is a culture of safety and a culture of responsibility.”

The FAA set a deadline of Feb. 19 to register previously owned drones, and new ones are supposed to be registered before the first flight.

The Academy of Model Aeronautics, which represents 180,000 hobbyists, has resisted government registration by arguing that the group’s members already mark their aircraft with identification. The group helped organize the Know Before You Fly program but considers the registration burdensome and unnecessary.

FAA registrants provide their name, physical address and email address. The credit-card transaction and $5 fee help confirm the person’s identity, although the fee was refunded during the first month.

The identification is intended to help police track down an operator if a drone collided with another aircraft or damaged people or property on the ground. The FAA receives hundreds of reports of drones flying too close to passenger planes, but the remote-controlled aircraft are difficult to trace.

The FAA has pursued hundreds of investigations into unsafe or illegal drone operation and opened 24 cases, Huerta said.

“We won’t hesitate to take strong enforcement actions against anyone who flies unmanned aircraft in an unsafe or illegal manner,” he said.