Just Stop Oil activists plotting a summer of disruption at airports vowed to use all means “necessary”, the group said on Monday.
The eco-warriors claimed they had won their “initial demand” for the UK government to end oil, gas and coal licences.
However, this “welcome step in the right direction” would “not be enough to protect our families and communities from the worst effects of climate breakdown”, it added.
In a statement, the climate change protesters threatened: “Therefore Just Stop Oil supporters will be taking action at airports this summer.
“This is not a course of action undertaken lightly, however action from governments must be commensurate with the scale of the crisis faced by humanity.
“Until that is the case, it is on the conscience of every ordinary citizen to utilise whatever mechanism is available to us to non-violently pressure for necessary change.
“Just Stop Oil supporters are trained in nonviolence and will undertake all possible steps to ensure that the safety of those using airports, as well as those in the air, will not be compromised by our actions.
“This includes avoiding going on any active or inactive runways.”
JSO has become notorious for blocking roads in central London, defacing artworks and disrupting sporting events.
The move came as two of its protesters appeared in court accused of damaging jets that were sprayed with orange paint at Stansted Airport.
Jennifer Kowalski, 28, of Dumbarton in Scotland, and Cole Macdonald, 22, of Brighton, are said to have used angle grinders to break through an airport fence at around 5am on June 20, Chelmsford Crown Court heard.
Singer Taylor Swift’s private jet had been there hours before the incident but was not affected.
Last week, Gatwick become the latest major airport to secure a High Court injunction to stop would-be environmental activists trespassing on its land after receiving police intelligence over protest plans in London on July 27.
Heathrow, London City, Stansted, Luton, Manchester, East Midlands, Leeds Bradford and Newcastle International airports have all obtained court orders against demonstrators in recent weeks.
Friday’s hearing in London came the day after five JSO protesters were jailed for several years for conspiring to organise protests that blocked the M25 motorway in November 2022, receiving sentences thought to be the longest ever given for peaceful protest.
Co-founder Roger Hallam was handed a five-year sentence at Southwark Crown Court.
Last month, the Metropolitan Police arrested 27 JSO supporters suspected of planning to disrupt airports this summer under a section of the Public Order Act that makes it illegal to conspire to disrupt national infrastructure.
