Air traffic was suspended at Copenhagen Airport on Monday evening due to reports of drone sightings, according to a post on X by live flight tracker FlightRadar24.
As of 10:05 pm CEST, 35 flights bound for Copenhagen Airport were diverted to other airports.
Airports in Malmö, Billund, Aarhus and Gothenburg received the most flights, according to the post. Flights at Copenhagen Airport resumed early Tuesday.
A police spokesperson told news agency Reuters that between two and four "large" drones were spotted in the area.
The unknown perpetrator was a capable drone pilot with the ability to fly them many kilometres to reach the airport, Jens Jespersen of the Copenhagen Police said during a news conference Tuesday morning.
The pilot seemed to be showing off their skills, he said.
Police chose not to shoot down the drones because the risk was too great, given the airport's full passenger capacity, the planes on the runways, and nearby fuel depots, he said.
Authorities also could not rule out the possibility of the drones being part of a Russian hybrid attack, he said.
Investigators are examining how the drones reached the airport — whether it was by land or possibly on boats travelling through the strategic straits into the Baltic Sea.
Local media show a significant police presence in the vicinity of the airport. Delays and cancellations continued Tuesday morning.
A drone incident on the same evening at Oslo airport forced all traffic to use one runway, according to Norwegian broadcaster NRK. Traffic later returned to normal, and it is unclear who was responsible.
Security concerns in northern Europe are heightened following an increase in Russian sabotage activities and multiple drone and fighter jet incursions into NATO airspace in recent weeks.
In 2023, London’s Gatwick Airport closed its runway for almost an hour after a drone was reported nearby.
In December 2018, more than 140,000 travellers were stranded or delayed during the Christmas season after dozens of drone sightings shut down Gatwick for parts of three consecutive days.
