The fourth day of demonstrations focused on London City Airport, where protesters attempted a "Hong Kong-style occupation of the terminal building" with hundreds blocking the main entrance.

The update on arrests comes as it was revealed Sir Christopher Hohn, who is worth STG1.2 billion ($A2.2 billion), made a personal donation of STG50,000 ($A91,400) to the environmental group, Britain's Daily Telegraph reports.

"I recently gave them STG50,000 because humanity is aggressively destroying the world with climate change and there is an urgent need for us all to wake up to this fact," Hohn told the newspaper.

The Children's Investment Fund Foundation, a charity co-founded by the billionaire, has also donated more than STG150,000.

Activists also blocked the entrance road, climbed on to the terminal roof and glued themselves to the entrance of the Docklands Light Railway (DLR) station serving the east London airport on Thursday.

Extinction Rebellion claims planned expansion of the airport is incompatible with meeting the government's legally binding commitment to cut emissions to net-zero by 2050.

An Aer Lingus flight from City Airport to Dublin was delayed when a protester on board stood up to deliver a lecture on climate change just as the plane was due to take off.

And one man, identified by Extinction Rebellion as former Paralympic cyclist James Brown, who is visually impaired, managed to get on top of a British Airways plane at the airport.

His actions were branded "reckless, stupid and dangerous" by Met Commissioner Dame Cressida Dick.

Police said more than 1,100 people have been arrested this week since protests began around Parliament and Whitehall on Monday, including around 50 at the airport on Thursday.

The protests in the capital are part of an "international rebellion" happening in cities around the world, calling for urgent action to tackle climate change and wildlife losses.

Australian Associated Press