Traffic at Geneva airport was interrupted due to climate activists on the tarmac on the first day of a business-aviation conference.

Some 100 activists supporting Greenpeace, Stay Grounded and other climate movement groups took part in a protest against private planes, coinciding with the European Business Aviation Convention & Exhibition, Greenpeace said in a statement Tuesday.

Shortly after 12 pm local time most of the activists had been forced to leave the area, AWP newswire reported. The airport said flights gradually restarted at 12:40 p.m.

Greenpeace said the protest wasn’t intended to disrupt air traffic. Some activists chained themselves to aircraft gangways and the exhibition entrance to keep prospective buyers from entering, the group said.