Twelve people have pleaded guilty to wilful obstruction after campaigners against airport expansion staged a protest near Heathrow Airport.
A small group of people ran on to the M4 and A4 roads, and lay down in front of oncoming traffic, causing a temporary disruption on Saturday, November 19.
Fifteen people aged between 21 and 67 were charged with wilful obstruction of the highway.
At a hearing at Ealing Magistrates' Court, Prosecutor Richard Doolan said protesters were joined together by plastic tubing and some of the defendants had to be cut away.
They were removed from the road in less than half an hour, he said.
The court heard that police knew a protest had been organised.
Guilty pleas were entered by Madeleine Allis-Petersen, 24, of Ealing; Joanne Louise Bodimeade, 28, of Lambeth; Alexis Delage, 25, of Lewisham; Tom Venner-Woodcock, 29, of Southwark, and Tess Lotter, 30, of Camden, all in London.
Also pleading guilty were Antoine Thalmann, 25, and Henry Owen, 23, both of Oxford; Simon Bramwell, 44, of Stroud, Gloucestershire; Ian Bray, 49, of Kirklees, West Yorkshire; Graham Lewis, 53, of Wells, Somerset; Thomas Harford, 26, of Bristol, and Sibi Moore, 21, of Sidmouth, Devon.
Lewis wore a white shirt in court which said: "Plane crazy runway hell."
They were all give conditional discharges, and each ordered to pay a victim surcharge and prosecution costs of £105.
Isabelle Anderson, 30, of Hebden Bridge, and Sophia Lysaczanko, 28, of Haringey, pleaded not guilty.
Anderson will go on trial on February 6 at Uxbridge Magistrates' Court, and Lysaczanko will go on trial at the same court on February 7.
Margaret Charnley, 67, of Bristol, was not at the hearing as she was excused from attending but a lawyer indicated a plea of not guilty.
