United Airlines chief Oscar Munoz apologised again for the forced removal of a passenger from an aeroplane 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.
Politicians on Tuesday pressed Mr Munoz and other executives, questioning practices such as overbooking.
Airline leaders said the incidents had pushed them to improve.
“We had a horrible failure three weeks ago,” Mr Munoz said. “It is not who we are. It is not this company and it is not … this industry.”
United has come under scrutiny for its forced removal of passenger David Dao from a flight on 9 April to make room for crew members.