The incident occurred on a July 2008 flight from Chicago's Midway Airport to Orlando, according to the lawsuit filed Monday in Cook County Circuit Court.

The boy, who was 14 at the time, asked flight attendants to switch his seat multiple times but "was emphatically told no," the lawsuit said.

"This was a little boy who was flying alone who was really, you know, in the care and custody of that airline," the family's attorney, Jeffrey Deutschman, said in a telephone interview. "They failed to protect him. They allowed an individual to get intoxicated on that flight. That person was harassing my client sexually as well as trying to give him drugs. He was a very scared little boy."

A spokesman for Southwest Airlines declined comment on the lawsuit.

The boy, who was flying to Florida to visit relatives, was so frightened by the experience that he refused to return home by himself, so his father flew down to accompany him home, according to Deutschman.

The family is asking for more than $50,000 for the "personal injury" that the boy sustained while on the flight.