Story highlights Woman's most recent arrest is in Chicago

Her life, motives are a mystery

(CNN) She's 66 years old with soft, white hair cut in a bob and the appearance of a genial grandmother, but Marilyn Jean Hartman has built up quite a collection of mugshots.

Nicknamed the "Serial Stowaway" for her history of unticketed jaunts on commercial flights, she has reappeared in the news after allegedly landing in London earlier this month without a passport or boarding pass.

More recently, she landed back in jail on charges of misdemeanor criminal trespass and violation of bail bond, after breaching bail by visiting Chicago's O'Hare International Airport -- from where she is said to have departed for the UK in the first place.

Her image may be familiar to airport and police cameras, but just how she manages to board planes and make trips remains a mystery, as does her personal life and background.

Little to nothing is known about whether she has or had a family and an employment history, where she is from and how or why she started her unauthorized travels.