Doctor David Dao's daughter speaks out about father dragged off United Airlines flight

David Dao's daughter says she was "shocked and horrified" by his treatment at the hands of United Airlines.

"My dad is a wonderful father," Crystal Dao Pepper told an emotional press conference. "He has raised five great children who will go on to do great things. He is a loving grandfather. At the end of the day he is the person we are trying to protect and take care of."

David Dao's lawyer, Tom Demetrio, said he would "probably" file a lawsuit against United Airlines after he was violently dragged off a plane when he refused to leave an overbooked flight.

David Dao's daughter Crystal Pepper, with attorney Stephen Golan, speaks at a news conference. Photo / AP

"The laws are there for the protection of each of us," Demetrio said.

"They have treated us less well than maybe we deserve. I conclude that based upon hundreds; literally hundreds, of tale of woe, of mistreatment by United, we want fairness in how people treat us, we want respect and we want dignity."

Asked whether Dao would sue the airline, he replied "probably".

Demetrio also said that Dao suffered a concussion, a broken nose and two broken teeth during the eviction and that he now required reconstructive surgery.

He said that if Dao did press legal action he would be "standing up for passengers everywhere who had been mistreated not only by airlines, but by corporations".

"I must say I don't think it's limited to the airline industry," Demetrio said. He said he thought "corporate America needed to understand that we all wanted: to be treated with the same respect as they treated their families".

Pepper said that on behalf of her dad and her entire family, she wanted to "express gratitude for huge outpouring of love and concern from all around the world the last few days".

"It has been a very difficult time for our entire family and we are truly grateful for your support. We were horrified and shocked and sickened to learn what had happened to him and to see what had happened to him," she said. "We hope that nothing like this in future ever happens again."