United Airlines is making headlines once again.

Sunday night, on a flight from Chicago to Louisville, a man was knocked out and forcibly dragged off an overbooked United Airlines plane. According to another passenger, the man was an older doctor. Video footage from Jayse D. Anspach shows the man screaming, while other passengers yell at the officers in shock.

In the video, one passenger can be heard saying, “Oh c’mon. You busted his lip.” While another screams, “Oh my God! Look at what you did to him!” One man sarcastically says, “Good work, guys, good work. Way to go.”

A United spokesman confirmed the incident via email to The Louisville Courier Journal :

“Flight 3411 from Chicago to Louisville was overbooked. After our team looked for volunteers, one customer refused to leave the aircraft voluntarily and law enforcement was asked to come to the gate.

We apologize for the overbook situation. Further details on the removed customer should be directed to authorities.”

The Courier Journal also obtained an account of the event from a passenger on UA3411, Audra D. Bridges. Bridges said passengers were told at the gate the flight was overbooked. United was offering $400 and a hotel for a passenger to take a later flight to Louisville on Monday afternoon.

All passengers were allowed to board the plane, but when boarding was complete, the flight crew announced four people needed to give up their seat to standby United employees.

The employees needed to be in Louisville for a flight on Monday. Bridges recounted the flight crew said the plane would not take off until the standby United employees were on the plane and bumped the offer up to $800. No one volunteered.

Bridges said a manager then boarded the aircraft and announced a computer would determine which four people were taking the later flight. A couple was selected first and they departed, then the man in the video was approached.

Bridges told Courier Journal the man was “very upset” and that he was a doctor who needed to be with his patients in the morning. The manager told the man security would be called if he did not leave voluntarily and the man said he was calling his lawyer. Security then removed the man.

According to Bridges, the man was allowed on the plane after his removal and medical personnel came to check on him.

A statement from United Air's CEO was tweeted out Monday afternoon.