By now, I assume you've seen the video of that passenger getting beaten up and DRAGGED off a United flight by police officers because he refused to give up the seat he paid for so a United employee could have it instead.
He's a 69-year-old named David Dao and, yes, he has some trouble in his past. He was a doctor, but he was convicted in 2004 of illegally prescribing painkillers to a patient.
The allegations also say he gave the guy painkillers because Dao was, quote, "sexually interested" in him and possibly having a sexual relationship with him, even though Dao's married to a woman.
He finally got his medical license reinstated in 2015, but in the process, it came out that he had some mental health issues and a mood disorder.
So far, United hasn't apologized, rather they blamed him for being belligerent.