United Airlines on Sunday forcibly removed a passenger from a flight departing Chicago O'Hare to Louisville Kentucky.

The passenger removed said he was chosen because he is Chinese.

United removed the man after overbooking caused a shortage in seats, when the airline wanted to fly four of its employees to Louisville.

An announcement was made offering incentives and compensation to anyone willing to leave the plane. When none of the passengers volunteered, the airline chose someone randomly.

United Airlines said the passenger in question and three others were removed from the flight after no one accepted the offer of a voucher to leave voluntarily. The other three passengers disembarked without incident, the airline added.

They also said they "followed the right procedures" in dragging the passenger off the plane, since he was one of the four selected but refused to move.

United Airlines spokesman Charlie Hobart said, "We followed the right procedures. That plane had to depart. We wanted to get our customers to their destinations."

The video shows police officers grabbing the man from a window seat, pulling him across the armrest, and dragging him by the arms down the cabin's aisle.

The passenger explained his refusal to budge by saying he was a doctor and needed to see be at the hospital to treat patients in the morning.

United Airlines Chief Executive Oscar Munoz said the incident was "upsetting" and apologized for "having to re-accommodate these customers."

One investor said he would "never fly" United Airlines again.

"Why did they choose an Asian out of so many passengers?" he said in a telephone interview. "Obviously Asians are the minorities."