Authorities said they were unable to neutralise the drones but added there was no threat to the public.
Flights were halted for several hours at Aalborg Airport, which also serves as a military base. Drone sightings began shortly before 10pm on Wednesday and ended just before 1am on Thursday.
The airports in Esbjerg, Sonderborg and Skrydstrup also were affected.
The latest drone activity comes just a few days after a similar incident at Copenhagen Airport, conducted by what police call a “capable actor”.
The Copenhagen drones grounded flights in the Danish capital for hours on Monday night, prompting concerns that Russia could be behind the flyover above Scandinavia’s largest airport.
The government has planned a news conference for Thursday morning. It was not immediately clear whether the Copenhagen flyover was related to the incidents later in the week.
