On Thursday, 25 September 2025, Denmark’s Aalborg Airport was closed due to drones in its airspace, just two days after drone sightings shut down Copenhagen airport. Following the incident, Denmark reached out to NATO and the EU while also placing three other airports – Esbjerg, Sønderborg, and Skrydstrup – on alert.
Several flights were rerouted from Aalborg airport, disrupting operations for both commercial flights and the Danish military, which also uses the base. According to the North Jutland Police, more than one drone was spotted with its lights on, starting at 9:44 p.m. on Wednesday, 24 September, and continuing until 12:54 a.m. on Thursday, 25 September. Police chief inspector, Jesper Bøjgaard Madsen, stated that they could not yet confirm how many drones were involved or who was responsible. Eurocontrol, the agency that manages European air traffic, had halted all flights to and from the airport until 4:00 a.m. Thursday.
❗️✈️🇩🇰 – Danish TV reports an increase in unidentified drone sightings in Esbjerg and Sønderborg, near the German border in southern Denmark.
— 🔥🗞The Informant (@theinformant_x) September 24, 2025
The National Police confirm similar incidents across multiple regions.
Royal Danish Air Force helicopters, carrying specialized… pic.twitter.com/bgzjfzFARF
According to the Danish national police, the drones behaved in a way that was similar to the drones that had shut down Copenhagen airport a couple of days earlier.
“It says something about the times we live in and what we as a society must be prepared to deal with,” said Prime Minister Mette Frederiksen earlier this week. Frederiksen also condemned the attack, labelling it “the most serious attack yet on Denmark’s infrastructure.” According to Frederiksen, Russian involvement in the incident could not be excluded, though Kremlin spokesperson Dmitry Peskov dismissed the claim as “baseless.”
2/2 “At the moment, we are witnessing a disturbing shift. Russian airspace violations. Unwanted drone activity in several European countries. Last night was an unmistakable reminder of the time we live in. That we need to protect our peace and security.”
— Statsministeriet (@Statsmin) September 23, 2025
At a press conference on Thursday morning, Danish Deputy Prime Minister and Defence Minister Troels Lund Poulsen said that Copenhagen was weighing whether to invoke NATO’s Article 4, which allows member states to consult allies when their security is threatened. Poulsen described the drone incursion as a hybrid attack carried out with a “systematic approach.” Authorities confirmed that permission has now been granted to shoot down any drones in the event of future incidents.
“We will track down those responsible,” Lund Poulsen declared, adding that Denmark has a range of military assets at its disposal, including F-35 fighter jets and naval frigates.
Denmark has not yet decided whether to activate NATO’s Article 4, says Defense Minister Troels Lund Poulsen. Last night’s events are described as a hybrid attack, with drones flown near Denmark by a suspected professional actor.
— GeoInsider (@InsiderGeo) September 25, 2025
NOST is now at operational readiness.
Authorities… pic.twitter.com/Vw7LiTBcPI
These incidents are part of a broader pattern of airspace violations in Europe. Denmark is not alone in its vigilance. Last week, Estonia and Poland invoked Article 4 to consult with allies over separate incidents, while Romania also reported Russian drones entering its airspace.
Moscow denied breaching Estonian territory and claimed that the Polish incident was unintentional, but provided no response to Romania’s report. After a meeting on 23 September, NATO released a statement condemning Russia’s actions and warning it would employ “all necessary military and non-military means” to ensure its defence.
