In the early hours of 25 September, unidentified drones were sighted over four Danish airports, including Aalborg Airport, a dual-use military and civilian facility, forcing temporary closures and flight disruptions there. The incidents come just two days after a similar drone intrusion shut down Copenhagen and Oslo Airport. Danish police, intelligence services, and the armed forces are investigating the attacks. The Prime Minister described the events as the “most serious assault” on critical infrastructure to date, noting they could be part of a series of suspected Russian drone incursions across Europe