Protest group Fathers 4 Justice has criticised the "shambolic" security at Heathrow airport and warned of more protests to come in the run-up to the London Olympics.
The protesters, who made a name for themselves campaigning for the rights of estranged dads while dressed as superheroes, have launched a fresh campaign of direct action in protest at the government not granting equal parenting rights to fathers.
In the groups's first protest against what they have dubbed the "Fatherless Games", two activists scaled the perimeter fence at Heathrow terminal 1.
Armed police arrested Tony Ashby and Andy Mason, but only after they spent 15 minutes inside the fence on the edge of the terminal's north runway.
They were able to lay pictures of their children on a piece of purple silk in front of the plane spotters' viewing area.
Campaign director Nadine O'Connor said: "The security at Alton Towers is better than that at Heathrow.
"This action marks our resumption of a campaign of direct action in the lead up to London 2012, the Fatherless Games.
"While ours was a peaceful protest, it should be a concern that just weeks before the Olympics, activists remained on the airfield for over 15 minutes, during which time we understand that the runway was closed."
The group pointed to a Yougov poll which found that 84 percent of respondents supported equal parenting rights.
As Fathers 4 Justice reignites its protests, splinter group New Fathers 4 Justice, which continued to protest when the main group toned down its actions to engage in political dialogue, has also warned of further disruption.
The original Fathers 4 Justice has stressed that it is not connected directly to the splinter group and takes no responsibility for its actions.
The group has claimed that it has a specially trained "superhero squad" that will take part in a series of protests during the games.
A spokesman said: "After years of fishing for our votes saying they would reverse the unfair policies of the so-called family court, David Cameron and the Tories smoke and mirror changes to the family laws system is not enough. Words will no longer do.
"The government never needed a new act of parliament to change the way that the courts applied the law. All it needed was to change the way that the courts applied it. That task is and was straightforward. It's procedure.
"It looks like we have no option but to continue non-violent, direct action as we approach the Olympics. We'd like nothing more than to be simply with our families, and happy in the knowledge our children would grow up with equal rights, but until anything is done this is the only way anyone takes any notice of our message."
The Norgrove report, which aimed to simplify and streamline the family court system, advised the government against equal parenting rights for divorced or separated fathers, claiming it would cause "confusion, misinterpretation and false expectations".