"The drones have disappeared and we have not taken any of them." Major airports in Norway and Denmark were forced to ground all flights after multiple drone sightings near runways on Monday and early on Tuesday.In Denmark, police saidwere spotted around Copenhagen Airport, the busiest in the Nordic region. Airspace was closed at 8:30pm local time, halting all take-offs and landings. About 30 departures and 20,000 passengers were affected.In Norway, Oslo Airport closed its airspace from midnight after a drone was spotted, a spokesperson for airport operator Avinor told Reuters. All departing flights were canceled or delayed, while arrivals were redirected to Gothenburg and Malmo in Sweden until the airport reopened at around 3:22am on Tuesday.