Protesters have stormed the runway at London City Airport, grounding flights indefinitely.
Activists in support of Black Lives Matter made their way airside around 5.40am at the central London airport.
It is the latest demonstration involving anti-racism activists, who brought traffic to a standstill outside Heathrow Airport - and carried out similar protests in cities around the country - in a co-ordinated day of action last month.
The campaigners, whose international movement was set up following the murder of black teenager Trayvon Martin in Florida four years ago, said Tuesday's action was taken "in order to highlight the UK's environmental impact on the lives of black people locally and globally".
The group called environmental inequality a "racist crisis" which disproportionately affects black people both in sub-Saharan Africa and the UK.
In a statement the protest group's UK division cited expansion plans at the airport as the cause of their action.
They said: "Recently London City Airport was given approval to expand its capacity, a move that consigns the local community in Newham to further deterioration of their environment. The average salary of a London City Airport user is 136,000 euros (£114,000) and 63% of them work in business, finance or other business services.
"It is an airport designed for the wealthy. At the same time 40% of Newham's population struggle to survive on £20,000 or less. When black people in Britain are 28% more likely to be exposed to air pollution than their white counterparts, we know that environmental inequality is a racist crisis."
Passengers are taking to Twitter to complain over the lack of information at the airport.
Others voiced concerns about security at the airport, among unconfirmed reports that the activists arrived by dinghy across the Thames.
The activists also plan to protest outside the Jamaican High commission this evening against the deportation of black people from the UK to the Jamaica due to their immigration status.