Drones ground Danish airport again as investigations widen

Aalborg Airport in northern Denmark canceled all arriving and departing flights on Wednesday night after several drones were sighted in its airspace, the second such disruption in three days. Nordjyllands Police said on X that drones had been observed near the airport and that the airspace was closed as officers investigated. An airport spokesperson did not specify how many drones were spotted. Four flights were affected, including two SAS planes, one Norwegian flight and one KLM flight, with inbound aircraft diverted to other airports.

The episode follows a previous wave of drone activity that disrupted Copenhagen airport earlier in the week and prompted questions about possible external involvement. Danish authorities have publicly discussed the possibility of sophisticated actors behind the disruptions. Police inspector Jens Jespersen said the signs pointed to a capable operator, noting factors such as the number and size of the drones, flight patterns and the timing over the airport, while declining to identify a specific actor.

Prime Minister Mette Frederiksen described the Copenhagen disruption as the most serious attack on Danish critical infrastructure to date, and officials have not ruled out Russian involvement. In parallel, Denmark’s intelligence service PET has warned of a high threat of sabotage, cautioning that the goal could be to stress the system or test responses rather than to cause direct casualties. “We are facing a high threat of sabotage in Denmark,” said Flemming Drejer, Director of Operations at PET, during a press briefing earlier this week.

Authorities have said the drones that closed Copenhagen’s airspace appeared from multiple directions, with some devices turning lights on and off before vanishing after several hours. Investigators are examining several theories about the drones’ origins, including the possibility that they were launched from ships along the Baltic Sea shipping lane that feeds Denmark’s main airport region.

While Russia has denied involvement in the Copenhagen incident, officials have warned that the region could be the subject of ongoing hybrid threats, and Danish security services say they will pursue all credible leads as investigators work to determine the sources and methods used.

On Tuesday, Danish authorities disclosed that flights at Copenhagen were diverted or grounded for hours after the drones were spotted, affecting an estimated 100 flights and some 20,000 passengers. About 31 flights were diverted to alternative airports including Malmo, Gothenburg in Sweden, Billund, Aalborg and Aarhus in Denmark, with the airport reopening in the early hours of Tuesday.

Norway’s Oslo Airport also reported drone sightings nearby, prompting a temporary closure and flight diversions there as well. In total, the string of disruptions has hit several European airports and heightened concerns about a coordinated campaign targeting critical infrastructure.

Airport officials at Aalborg said the effects on schedules were felt across the region as inbound and outbound flights were re-routed, leaving some passengers stranded or unstably scheduled. Authorities stressed that investigations would continue and that security measures would be intensified at Danish airports as a precaution.

This is a developing story and updates are expected as police and intelligence services gather more information on the drone sightings and assess potential links to broader security threats in the region.