A woman who's been dubbed a serial stowaway was sentenced Tuesday to 18 months of probation after pleading guilty to sneaking past Chicago airport security last year, boarding a plane and flying to London without a ticket.

As part of her plea deal, Marilyn Hartman, 67, can't go to Chicago's O'Hare or Midway airports without a ticket. She entered the plea to a criminal trespassing charge but had originally faced counts of felony theft, burglary and other charges.

"I do apologize for the airport and ... causing problems for them," Hartman told Cook County Judge Peggy Chiampas.

The plea is the latest chapter in a story that's played ou t over the past decade in Chicago, Hawaii, San Francisco, Florida and elsewhere. Hartman has been nabbed in and near airports dozens of times and made it onto planes maybe a half-dozen times.

Authorities have said she boarded the flight to London by walking past two British Airlines ticket agents who were checking other passengers. Hartman darted into a small room off to the side and walked quickly past customs and a Border Patrol agent who was looking at passports of people entering the ramp.

Hartman was arrested after her London trip and free on bond in January 2018 when she was again discovered wandering at O'Hare. This time, a judge ordered her held without bond and she was later found unfit for trial. Hartman spent time at a state mental institution and in July she was moved to a halfway-house style mental health center in Chicago called A Safe Haven.

The judge Tuesday praised Hartman for receiving a glowing progress report from the center's staff.

"A Safe Haven has been your safe haven, and I am really proud of the progress you have made," Chiampas told Hartman.

The facility has agreed to help Hartman find permanent housing.