A British judge found 13 environmental protestors guilty of aggravated trespass and entering a security-restricted area, saying they will likely face jail time after sneaking onto the north runway at Heathrow Airport last summer and chaining themselves to railings.

The group—which is literally called Plane Stupid—snipped the fence and broke into the airport to protest a planned third runway, which they say will contribute to climate change.

Their actions forced the cancellation of 25 flights, causing many more delays and leaving thousands of passengers stranded, leading the judge to conclude the cost of their stunt was “absolutely astronomical.”

Britain’s environmentalists remain unapologetic, despite creating a hellish hassle for innocent travelers. Greenpeace UK released a statement in support of the trespassers. And the protestors’ organization also released a statement: “Plane Stupid will be here. We’re in it for the long haul.”

 Now, that’s just plain…