Copenhagen Airport was left paralysed for four hours on Monday night, causing chaos for passengers as planes were stopped from taking off or landing.
All traffic was halted after unidentified drones were ‘spotted nearby’ at around 8.26pm local time.
The airport reopened at around 12.30am on Tuesday but delays and cancellations were expected to continue.
Between two and three ‘large’ drones were sighted in the area, Copenhagen police spokesperson Henrik Stormer said, and the airport revealed the drones remained present in the area for several hours afterwards.
At least 35 flights were diverted to other sites, including Malmo and Gothenburg, Sweden, and Billund, Aalborg, and Aarhus, Denmark.
Later in the evening, Oslo Airport in Norway was also forced to close and divert its planes after drones were spotted in the vicinity.
Two people were also arrested in the Norwegian capital after drones were seen at a military site.
At a press conference in Copenhagen, Jakob Hansen, deputy police inspector at the Copenhagen Police, said they are working with the Danish Armed Forces on the incident, saying that ‘measures will be taken’.
The police could not say where the drones came from, but said they disappeared on their own and have not been seen since.
He said the police ‘do not know at this time’ whether the drones were Russian.
Deputy Inspector Hansen confirmed that police would work closely with Norwegian police after a number of drones were seen in Oslo.
Police officers seen at Copenhagen Airport after all flights were diverted due to drone sightings
He said he understood people’s fears about the drones in Danish airspace.
He added: ‘I can understand that the security situation, as it is, makes people think about many things. If people have become afraid, then I can understand that.
‘The police cannot yet say anything about where the drones came from, nor can they say where they subsequently flew.’
However, Hansen said there was no indications that the drones have posed a danger to Danes.
Police said they were not concerned about the possibility of the drones attacking and said passengers who were in planes were not in danger.
They said they will host a further press conference at 7am local time.
During the closure, one plane was allowed to make an emergency landing at Copenhagen Airport as it did not have enough fuel to divert.
Earlier in the evening duty officer Anette Ostenfeldt warned that the drones were still ‘flying back and forth, coming and going’, several hours after the closure.
She could not say if the drones were military or civilian devices.
‘But they are bigger than what you as a private individual can buy,’ Ostenfeldt said.
An airport spokesperson told local news outlet BT that the drone sighting was ‘unusual’.
Police said that between two and three ‘large’ drones had been sighted in the area
She said: ‘It’s procedure that you can neither take off nor land, and you still can’t. The police are investigating the matter, until they have more information, the airspace is closed.
‘We hope that passengers can soon depart safely and land safely.’
They also reportedly called in extra staff for several positions.
Passenger Mikael Belstrup told the news channel he was on a flight from Amsterdam to Copenhagen which was diverted to Billund.
He said: ‘We were told that Copenhagen Airport was closed due to drones and that the staff didn’t know anything. We are still in the plane and they are refueling it so we have the opportunity to come back if or when the airport opens.’
Another passenger told local media that they boarded a plane to Paris for a school trip.
She said: ‘The atmosphere is quite tense, and no one really knows what is going on.
‘What makes it unsafe to sit here is that we can see that there are so many police surrounding us and so many blue lights.’
Many flights to and from Copenhagen have been severely delayed or cancelled
Another eyewitness said they saw blue flashes from the runways, three police cars and around eight officers.
One flyer who had been traveling from Krakow, questioned whether there was a possibility the drone was meant to be in Polish airspace.
‘It was really uncomfortable. Really uncomfortable. When you think about everything that’s happened in the last few weeks,’ he told BT.
Later, at around 9:00pm local time, a similar alert occurred in Oslo, Norway, after drones were spotted over the Akershus Fortress, a military site.
Norwegian police said they detained two Singaporean citizens in connection with the incident.
Norwegian police detained the two foreign nationals who were operating a drone over Akershus Fortress, which houses the headquarters of the Norwegian Armed Forces and the Ministry of Defense, according to the Norwegian state broadcaster NRK.
Drones were then spotted near Oslo airport, forcing it to close and divert all of its flights to other destinations.
Norwegian police said they had not been able to locate the drone or its owner.
They added that there is no basis to say that it is related to drones at Copenhagen Airport.
Copenhagen Airport was previously closed in January for almost two hours following a drone sighting.
