At least two flights from Gatwick were diverted and its runway was closed after a drone flew too close to the airport in southern England.
A statement from the airport said that the the runway was closed for two periods of nine minutes and five minutes after the incident on Sunday evening (2 July) which Sussex police is now investigating.
"Due to reports of a drone observation in the vicinity of the airfield, runway operations at Gatwick were suspended between 18:10 BST and 1819, and again from 1836 to 1841, resulting in a small number of go-arounds and diverts.
"Operations have resumed and the police continue to investigate," Gatwick said in a statement.
While some planes had to circle the airport, Niamh Slatter, from Sussex, told the BBC that her BA flight from Valencia was diverted to Bournemouth.
"We were due to land 15 minutes early, but ended up circling over the south coast for a while. The crew were brilliant and explained that we were being held due to a drone in the airspace at Gatwick but that they would tell us when they had more information.
"Our attempted landing at Gatwick was aborted quite late as the drone had been spotted again, so we were told that the flight was being diverted to Bournemouth airport," she said. Another plane was diverted to Stansted.
In November 2016, a passenger jet came close to colliding with two unmanned drones in the skies above London.