Reading Time: 2 minutesCopenhagen Airport , the busiest in the Nordic region, said it reopened early on Tuesday after drone sightings halted all take-offs and landings for nearly four hours, with Norway’s Oslo Airport also re-opened after it had shut its airspace over a drone. “The police have launched an intensive investigation to determine what kind of drones these are,” Copenhagen Police Deputy Assistant Commissioner Jakob Hansen told reporters. It had been shut since midnight (2200 GMT) due to a drone observation, with all flights diverted to the nearest airport. After it reopened, Copenhagen Airport said on X that delays and some cancelled departures would persist and urged passengers to check with their airlines. In 2018, drone sightings over the runway at Gatwick near London stranded tens of thousands of passengers and disrupted hundreds of flights at the height of the holiday season.