Some people saw drones flying over Aalborg airport in Denmark. The police closed the airport because of the drones. Three other airports saw drones too, but they did not close. The police do not know who is flying the drones or why.

Some planes could not land at Aalborg airport. The police and army are watching the airport. They say people are safe, but they must stay away from the airport. The police want to stop the drones if they can.

Last week, other airports in Europe also saw drones. Some people think Russia is sending the drones, but Russia says it is not true. NATO says it will protect its countries if there is a problem.