ReutersOperations at Copenhagen Airport will resume after flights were suspended for several hours after the drone sighting.
Authorities say two or three large drones were seen flying in the area around Copenhagen Airport.
Takeoffs and landings at the airport were suspended for approximately four hours.
In a statement, the airport warned of continued delays and cancellations, urging passengers to check the status of flights with the airline.
A Copenhagen Airport spokesperson confirmed that the airport airspace was closed around 20:30 local time (19:30 BST) due to the unidentified drone.
“We cannot take off or land an aircraft at an airport, and as a result, some flights have been diverted to other airports,” they said in a statement.
“The police are investigating the issue and we currently need a timeline to resume.”
Flight tracking website Flightradar24 reported that at least 35 flights detained in Copenhagen have been deported as a result of the airport closures.
Norwegian police also confirmed to local media outlet NRK that drone was observed near Oslo Airport on Monday evening.
A police spokesperson told NRK that they had “taken steps” to find the drones, and that all air traffic was moved to a single runway for “safety reasons.”