A London City flight was delayed after an Extinction Rebellion activist stood up to deliver a lecture on climate change.
The protester, who was a passenger on the flight, was arrested after refusing to sit down as the plane was due to take off to Dublin.
He said he was "extremely sorry for the inconvenience" but when asked to take his seat, replied "I wish I could ... we have two generations of human civilisation left".
The demonstration was part of a three-day occupation of London City airport in a protest against climate change.
The “Fly today, gone tomorrow” sit-ins intend to “peacefully occupy and shut down” the airport terminal by protesters lying, sitting or gluing themselves in front of the departure and arrival gates.
WATCH: Protesters assemble at London City airport
However, despite the scene on board the flight and scores of activists blocking the way for passengers at the airport’s main entrance, staff clime flights are operating as normal.
A spokesman for the airport said: “We can confirm that a number of protesters have arrived at London City Airport.
“We continue to work closely with the Metropolitan Police to ensure the safe operation of the airport, which remains fully open and operational.”
Deputy Assistant Commissioner Laurence Taylor from the Metropolitan Police said: "Targeting an airport and inconveniencing travellers in this way is wholly unacceptable and irresponsible.
"The consequences of committing offences at airports are serious; individuals breaking the law are being, and will continue to be, arrested and prosecuted where appropriate."
The climate change campaign group has said the action is a “homage to the style of the Hong Kong democracy protesters”.
Earlier this year Hong Kong airport was shut down and more than 200 flights cancelled in a series of mass protests.
In London, Extinction Rebellion demonstrators, have brought the city to a standstill in a demand for immediate government action on the environment.
Actors Benedict Cumberbatch, Olivia Colman and Sir Mark Rylance have all plledged their support for the movement.
More than 800 people have been arrested since the rallies began on Monday – rapidly approaching the total of 1,100 arrests made across the entire two-week protest back in April.