After initially defending the airline’s policies, United’s chief executive apologized. United has offered a refund to every passenger on the flight and has promised to no longer have the police remove passengers from planes that are too full.

“This horrible situation has provided a harsh learning experience from which we will take immediate, concrete action,” the company said in a statement Thursday. “We have committed to our customers and our employees that we are going to fix what’s broken so this never happens again.”

Those assurances have done little to quell the outrage, visible in the phalanx of news cameras from around the world that assembled Thursday to hear from Mr. Demetrio and Crystal Dao Pepper, one of Dr. Dao’s five children. Mr. Demetrio said he thought the company’s apology had been “staged,” and said he was not aware of any attempts by United officials to contact Dr. Dao.

“What happened to my dad should have never happened to any human being regardless of the circumstances,” Ms. Dao Pepper said. She said her father was catching a connecting flight in Chicago to his home in Louisville, Ky., after a vacation in California.