London (CNN) — An environmental activist climbed on top of a plane on the runway of London's City Airport Thursday, as part of a series of protests at the site by the group Extinction Rebellion.
Videos showed the man, identified by the group as para-athlete James Brown, lying on the British Airways aircraft for over 20 minutes as authorities attempted to help him down.
Extinction Rebellion are attempting to "shut down" London's fifth largest and most central airport from Thursday to Saturday, to protest a planned expansion of the site which the group says will make it "impossible" for the government to reach carbon neutral status by 2050.
Hundreds of activists blocked the main entrance to the site, while another delayed a flight by two hours by giving a lecture on climate change just before take-off.
Passengers filmed the man standing up in the middle of his aisle and reading aloud on his phone as the Aer Lingus flight to Dublin was preparing to leave.
"We have two generations of human civilization left if we carry on doing what we're doing," the protester said, as passengers heckled him and urged staff to remove him from the flight.
The flight finally took off after 11 a.m. local time.
Nicholas Watt, a BBC journalist on board the flight, tweeted: "Plane was at the end of runway. So the pilot taxied back to gate where plane was met by throng of police. They came on board and escorted the protester off the plane."
"And the final irony of the climate protest on our flight. We cannot take off until we have taken on extra fuel...to replace the fuel used up during the protest, our pilot notes with humour," Watt added. He said passengers applauded crew members for how they dealt with the protester.
Aer Lingus added in a statement that a man was taken off the flight for "disruptive behaviour on board," before a security check of the aircraft was carried out.
The protests are part of the group's week of action in the capital and across the UK, which have seen roads closed near the Houses of Parliament and near other landmarks. Demonstrations are also being held in various other cities around the world.
A protester is arrested after refusing to sit down on a flight to Dublin.
Lola Newton, a protester from Edinburgh, told CNN: "I'm here to support the disruption of the things that need to be disrupted to avert climate meltdowns."
Newton added of the police response: "At times it's been aggressive but mostly British police are pretty calm ... go anywhere else in the world (and) this wouldn't be possible, so I'm very grateful for their behavior."
Cressida Dick, the head of London's Metropolitan Police, said in a video statement on Thursday that more than 600 protesters have been arrested across London in the past two days.
"If you want to protest, you can go to the middle of Trafalgar Square," Dick said. "If you are protesting in the other sites, you're acting unlawfully, we will arrest you, I imagine you will go to court and you're very likely to get a criminal record."