What we know about mysterious drone sightings in the United States

 By Zoe Sottile, Josh Campbell and Artemis Moshtaghian, CNN

👉jamming" rather than destroying them in the air.

👉But shooting down unidentified aircraft poses its own problems. "It's not as though anyone can just take down a drone in the sky. That in and of itself would be dangerous," Mayorkas told CNN's Wolf Blitzer.

👉Similarly, a source familiar with the national investigation into the aircraft told CNN shooting them out of the sky would be "beyond risky," posing an unnecessary risk to people on the ground and legal challenges.

👉The source noted the government has various strategies that can be deployed if a drone poses an imminent threat, but so far, the mysterious flights have not been deemed threatening.

👉"Blowing it out of the sky is the last resort," the source said.

Who regulates drones?

👉Part of the challenge in monitoring drone activity stems from the fact regulation of the skies is almost entirely under federal jurisdiction, according to the chief executive of a company tracking unauthorized drone flights.

👉"The laws that regulate aircraft are not built to empower police to deal with the drones," Axon chief executive Rick Smith told CNN News Central Friday, "so if your local state fair has a drone coming towards it that police believe might be dangerous, right now there's nothing they can do about it."

👉FAA regulations allow operators of recreational drones to fly up to 400 feet above the ground in airspace not controlled by FAA air traffic controllers. The FAA does grant waivers on a case-by-case basis to those wanting to operate drones in more congested airspace or at higher altitudes.

👉Missy Cummings, one of the Navy's first female fighter pilots, thinks there would be a different level of action from authorities if people were in danger from the possible drone sightings.

👉"I think if this were a legitimate threat, we would be seeing different kinds of action," Cummings, a professor at George Mason University, told CNN's Fredricka Whitfield Sunday.

👉"People don't want to hear this, but probably a significant number are manned aircraft, although I do think that they are legitimately seeing drones," Cummings said.

👉CNN's Samantha Waldenberg, Sam Fossum, Betsy Klein, Annie Grayer, Edward-Isaac Dovere, Andy Rose, Hanna Park, Brad Lendon, Oren Liebermann and Travis Nichols contributed to this report.