The closure, which began shortly before midnight on Sept. 25, forced flight KL1289 to return to Amsterdam and canceled flight SK1225 from Copenhagen, according to police and airport authorities.
Although operations have since resumed, officials cautioned that the facility could shut down again if drones reappear.
Danish Defense Minister Troels Lund Poulsen condemned the repeated incursions as a “hybrid attack,” saying they were not coincidences but rather “systematic action” involving multiple types of drones. He warned of a potential coordinated campaign against the country’s airspace that poses a threat to national security.
The incidents have sparked public alarm, with police receiving hundreds of calls from residents reporting suspicious objects in the sky. Some of these sightings occurred near sensitive military sites, including the Aalborg Air Base, which is home to Denmark’s elite Jægerkorps special forces and transport aircraft, as well as the Skridstrup Air Base, which is home to F-16 fighter jets.
Local police said they are questioning witnesses in detail to determine whether the objects were indeed drones and not airplanes or bright stars. They urged eyewitnesses to film suspicious objects and send the recordings for analysis.
Local media also reported that the Russian military ship Alexander Shabalin was present in international waters near Denmark during the drone incidents, raising speculation about a possible link. The vessel had switched off its identification system, remaining undetected for a period. Authorities have not confirmed any connection.
This comes just days after Copenhagen Airport was forced to halt operations for several hours on Sept. 23 due to drones entering restricted airspace.
Oslo Airport in Norway temporarily shut its airspace following a similar incident with unidentified UAVs.