LONDON • London’s Gatwick Airport was operating without problems Sunday, but the fugitive drone operators who brought incoming and outgoing flights to a standstill over multiple days remained at large — and a potential threat — after police cleared two local residents who were arrested as suspects.

Sussex Police were hopeful they had halted the disruptive and costly drone incursions during one of the heaviest travel periods of the year with Friday’s arrests of a couple who live near the airport. But they were released Sunday, and police said they were no longer suspects.

Tens of thousands of passengers suffered through long flight delays or were stranded by cancellations after two drones were reported seen above the airfield at Gatwick on Wednesday night, prompting an immediate suspension of all air traffic.

Sussex Chief Detective Jason Tingley said Sunday he could not rule out new drone activity at Gatwick or other U.K. airports.

He also said it was possible that witnesses who reported sightings after the first ones aroused alarm were mistaken.

A plane comes in to land at Gatwick Airport. Flights resumed at London’s Gatwick Airport on Friday after drones sparked the shutdown of the airfield for more than 24 hours.

the associated press