All flights at London City Airport have been disrupted after protesters gained access to the runway.
The Met Police said it was called to the site at about 05:40 BST after nine protestors "locked themselves together" on the runway.
The Black Lives Matter UK movement has confirmed to the BBC it is responsible for the protest.
The airport said inbound flights were being diverted and it hoped to "resume operations as soon as possible".
Black Lives Matter UK tweeted: "Activists in support of BLMUK #Shutdown London City Airport to protest the UK's environmental impact on black people."