The United Airlines passenger who was hauled off an overbooked plane is a poker-playing doctor from Kentucky with a sordid past. Dr. David Dao, 69, who was captured in a now-viral video being forcibly dragged off the Louisville-bound flight at Chicago’s O’Hare Airport on Sunday, was working as a doctor specializing in pulmonary disease in Elizabethtown when he was convicted of trading prescription drugs for sex favors. According to documents filed with the Kentucky Board of Medical Licensure, Dao was arrested in 2003 on the drug-related offenses following an undercover investigation.