Almost 50 protestors are being trained up to cause chaos at Heathrow by attending militant training camps - including many middle-aged women.
Visitors to the latest secret workshop in west London, the majority of whom have never taken direct action before, acted out role-plays including storming the AGM of a major airline.
Campaigners, most of whom belong to protest groups HACAN and NoTRAG, also learned about their legal rights when carrying out risky stunts on Sunday.
HACAN chairman John Stewart said: "Although neither HACAN nor NoTRAG are direct action organisations, what was clear from Sunday's session was that the most unlikely people are prepared to take direct action if that's what it takes to stop expansion at Heathrow.
"Although there were some younger people there, the typical person who attended was over 40 and female.
"It showed that, if Gordon Brown and Geoff Hoon plough on with their expansion plans regardless of the facts, they will face direct action from the unlikeliest of people."
Activists, who last August blockaded BAA's HQ in Bath Road, have said they are pepared to be arrested in a series of non-violent demonstrations - possibly including a mass invasion of Heathrow's runways.
They only plan to take action if the Government gives the nod next month for a third runway and a series of other measures, which could increase Heathrow's capacity nearly 50 per cent to 700,000 flights a year.
The training camp was run by Seeds for Change, which describes itself as a 'non-profit activist co-op'.
Participants intend to organise future meetings where they will plan specific actions should expansion plans get the green light