United Airlines chief executive Oscar Munoz again apologised for the forced removal of a passenger from an aircraft last month as he testified in Washington.
He spoke at a congressional hearing convened after recent incidents exposed mounting frustration with US airlines and the flying experience.
Munoz and other executives were pressed by politicians who, questioned practices such as overbooking.
Airline leaders said the incidents had pushed them to improve.
“We had a horrible failure three weeks ago,” Munoz said. “It is not who we are. It is not this company and it is not … this industry.”
His comments came as a video emerged of two passengers fighting on an All Nippon Airways flight due to take off from Tokyo for Los Angeles.
Passengers look shocked as flight attendants try to stop the fight and separate the two men.
The unruly passenger, identified as a 44-year-old American, was arrested and charged with assault after being removed from the aircraft.
ANA said: “The individuals involved have been dealt with appropriately by local law enforcement.”
United has come under scrutiny for its forced removal of passenger David Dao from a flight on April 9 to make room for crew members.
The airline has settled a lawsuit and announced a series of policy changes including boosting the amount of money staff can offer passengers to take a different flight.
American Airlines also suspended a staff member after a clash with a passenger over a baby pram.
Consumer groups, and some US politicians, said airlines should do more and raised the threat of greater regulation.
“As a general rule, I don’t believe in over-burdening our businesses with regulation, or re-regulating industries that have been successfully de-regulated,” said Bill Shuster, the Pennsylvania Republican who heads the committee.
“But I shouldn’t need to remind you that Congress will not hesitate to act, whenever necessary, to ensure your customers are treated with the respect they deserve.”