One of Germany's main regional airports had to halt flights on Wednesday morning after climate activist protesters glued themselves to the tarmac.
Cologne-Bonn Airport after said "unauthorised people" gained access to the airfield on Wednesday morning, leading to all flight operations being suspended as police moved in.
A number of inbound flights were diverted to other nearby airports before police said they had completed their operation at 09:15 (07:15 GMT).
Cologne-Bonn Airport said flights were resuming but that delays and cancellations should be expected throughout the day.
It urged passengers to check with their airline or tour operator for updates.
The activist group Last Generation said five people had glued themselves to the tarmac and published pictures of a member with his hands glued to the taxiway.
Last Generation said it wanted the German government to pursue a global agreement to exit oil, gas and coal by 2030.
The group said "similar peaceful, civil protests at airports" were planned for Wednesday across Europe and North America.
In Finland, protesters were pictured blocking security gates at Helsinki Vantaa Airport and activist group Oil Kills said five of its protesters had been intercepted at Barcelona El Prat airport.
Elsewhere, three activists broke the perimeter fence at Oslo's main Gardermoen Airport on Wednesday morning.
The trio were reportedly removed just over 30 minutes after they entered the airport and airport officials said they had found an angle grinder near a hole in the fence.
Cologne-Bonn is Germany's sixth-busiest airport - behind Hamburg, Düsseldorf, Berlin Brandenburg, Munich and Frankfurt.
In May, Munich Airport was forced to shut for two hours after six climate protesters glued themselves to a runway.
Eight people were arrested, but the disruption led to 11 flights being diverted and about 60 cancellations, an airport spokesman said.
In the aftermath, Germany's Interior Minister, Nancy Faeser, said security measures at Munich Airport "would be reviewed".
