Denmark’s Aalborg airport, a hub for both commercial and military flights, was shut down late Wednesday after drones were spotted in its airspace, police said. The closure lasted about three hours and forced the diversion of three flights.

The disruption comes just two days after drone activity closed Copenhagen airport for four hours, an incident the Danish government described as the most serious attack yet on its critical infrastructure. National police said the Aalborg drones followed a similar flight pattern to those over Copenhagen.

denmark airport drones

A screen capture of a post on X by FlightRadar24 on September 24, 2025 shows diverted flights after Denmark’s Aalborg airport was closed due to drones in its airspace. FlightRadar24.com/Handout via REUTERS THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. NO RESALES. NO ARCHIVES. MANDATORY CREDIT

Military base also affected

Aalborg airport also serves as a base for Denmark’s armed forces. The military confirmed it was supporting local and national police with the investigation but declined further comment. Authorities in Southern Jutland later reported drone sightings near Esbjerg, Sonderborg, and Skrydstrup, home to Denmark’s fleet of F-16 and F-35 fighter jets.

Police in Northern Jutland said “more than one drone” with lights visible was first detected at 9:44 p.m. local time on Wednesday and left the airspace at 12:54 a.m. Thursday. Eurocontrol, which oversees European air traffic, placed Aalborg’s arrivals and departures at a “zero rate” until 4 a.m. GMT.

European concerns grow

The recent incidents have heightened security fears across Europe. Norwegian authorities briefly closed Oslo airport on Monday after a drone sighting, while European Commission President Ursula von der Leyen warned of a “pattern of persistent contestation at our borders.”

Investigators have not determined who is behind the incursions. “It is too early to say what the goal of the drones is and who is the actor behind,” a Northern Jutland police official said. Efforts to bring down the drones have so far failed.

Russia’s ambassador to Denmark has rejected suspicions of Russian involvement in the Copenhagen disruption as “ungrounded.” Meanwhile, Denmark and Norway remain in close contact as their investigations continue.

Nationwide reports

National police commissioner Thorkild Fogde said authorities have received a surge of drone reports since Monday, though most were unrelated to security concerns. “Some of them do [matter], and I think the one in Aalborg does,” he told reporters according to Reuters.

Police stressed there was no immediate danger to passengers or residents in Aalborg. The first flights departed early Thursday morning once the airspace was cleared.