For years, law enforcement agencies in several states have known her for her seemingly endless and weird habit of getting on planes without a ticket, a boarding pass or a passport.
She was arrested twice in two days in July 2015 for attempting to sneak through airports without a valid ticket.
Marilyn Hartman slipped on to the jet with a large group after she got through security at Chicago's O'Hare International Airport and boarded a flight to Heathrow, police said.
Hartman got past TSA screening at a domestic checkpoint at Chicago O'Hare, then took a shuttle to the worldwide terminal.
Hartman had reportedly wandered around Chicago O'Hare for two days without being questioned. She was then sent back to O'Hare and arrested by USA law enforcement officials.
She then boarded a flight to the United Kingdom and was detained by British Customs Officials at Heathrow International Airport in London on January 15, police said.
The Chicago Department of Aviation released a statement, advising that no passengers had been put at risk by the episode. "During the initial investigation it was determined that the passenger was screened at the security checkpoint before boarding a flight".
She added in a statement: "We are working with our law enforcement partners to support a comprehensive and thorough investigation, while continuing to maintain the highest levels of security at O'Hare Airport".
The TSA is no match for Marilyn Hartman. At a hearing Saturday afternoon, a judge ordered her released on her own recognizance, but ordered her to undergo psychological treatment and stay away from O'Hare and any British Airways planes.
"And it's not as if she is, 'Catch me if you can.' It's nearly like, 'Just come catch me, ' " Assistant State's Attorney Jeff Allen told reporters during the hearing.
At the time she was sentenced to jail, Hartman had been living at a mental health facility on the Near North Side of Chicago before violating the terms of her probation by leaving the facility and going to O'Hare.
Authorities are unsure of her motives, but the judge presiding over her 2016 case said he believed she was "addicted to the attention".