The coordinated protests have also other European airports from Norway to Switzerland.
Climate activists have glued themselves to the runway at Cologne-Bonn Airport, one of Germany's biggest airports.
Flights were stopped but they have now resumed, with the airport saying: "The police operation at Cologne/Bonn Airport is over. Flight operations have resumed. Disruptions in the form of delays and flight cancellations are to be expected during the course of the day."
Police said five people glued themselves to a taxiway at the airport early this morning and officers were trying to dislodge them, German news agency dpa reported. By 8.30 am, two of them had been removed.
The Last Generation activist group said in a statement that supporters in several small groups cut through the perimeter fence, approached the airport and then glued themselves to the asphalt with a mixture of sand and glue.
What are the protesters' demands?
Acting under the banner 'Oil Kills' the protesters say: "We are demanding our criminal governments phase out oil, gas and coal by 2030 by signing a binding international treaty."
Through coordinated actions around Europe, they ask, "our governments... to stop extracting and burning oil, gas and coal by 2030 as well as supporting and financing poorer countries to make a fast, fair, and just transition."
In Finland, activists were photographed obstructing the security gates at Helsinki Vantaa Airport.
In Norway, three activists reportedly breached the perimeter fence of Oslo’s Gardermoen Airport. Norwegian media reported that these individuals were removed by authorities within 30 minutes of gaining access.
"My country is actively contributing to a climate crisis that is going to kill millions of people and destroy countless other species," said Anders, 25, a student who took part in the protest with Folk Mot Fossilmakta (People against Fossil Power). "I ask Norway to join other countries in creating a fossil fuel treaty that will end the use of fossil fuels by 2030.”
Barcelona airport in Spain was targeted by supporters of Futuro Vegetal (Vegetal Future) this morning, demanding an end to fossil fuels and a shift to plant based agri-food systems. They were intercepted - one has been arrested and taken to court while the others have been fined for attempting to disrupt airport traffic.
Supporters of Liberate Switzerland, meanwhile, blocked roads heading to Zurich and Geneva Airports, calling for an end to fossil subsidies.
"I cannot stand by silently while fossil fuels continue to kill thousands and governments continue to expand their use," said protester Rita Straub, 74, a retired software analyst. "I am committing civil disobedience to shake things up, to exert pressure. Action must be taken. Now."
In the UK, seven Just Stop Oil supporters were also arrested on the perimeter road outside Heathrow Airport at 9 am today.
Governments are bringing in tougher legislation against airport protesters
These are the latest of several airport protests by climate activists in recent years that caused disruption to flights.
Last week, the German Cabinet approved legislation that would impose tougher penalties on people who break through airport perimetres.
The bill, which is still under consideration by lawmakers, foresees punishment ranging up to a two-year prison sentence for people who intentionally intrude on airside areas of airports such as taxiways or runways, endanger civil aviation, or enable someone else to. So far, such intrusions can only draw a fine.
A sentence of up to five years would be possible in cases where someone forces their way into an airport with banned objects such as a weapon, certain knives, poisonous substances, or if the intrusion is intended to enable or cover up another offence.