The CEO of United Airlines has apologised for the "truly horrific" incident in which a passenger was forcibly dragged, screaming, from a flight.
Oscar Munoz said he "continues to be disturbed" by the incident, captured on a video that went viral on Twitter.
He said the company would "fix what's broken so it never happens again".
The family of the passenger, David Dao, issued a statement expressing gratitude for the "outpouring of support". He is undergoing treatment at a Chicago hospital.
The footage taken inside the airliner shows a man being pulled out of his seat and dragged, screaming, down the aisle. He is later seen with blood on his face.
The flight from Chicago to Louisville, Kentucky, on Sunday evening had been fully booked, United spokesman Jonathan Guerin told USA Today newspaper.
The airline wanted to get four passengers to leave the flight to make room for four staff members who were needed in Louisville the next day.
United had previously described the flight as overbooked.