The lawyer of David Dao, the man dragged from a United Airlines plane, has said he wants the case to start international discussion on airlines who have "bullied" passengers "for a long time".

Footage of a bloodied Dr Dao being dragged off an overbooked flight by airport security officers on Sunday night has been viewed hundreds of millions of times.

It has now emerged the 69-year-old, who lost two front teeth and suffered a broken nose, will require reconstructive surgery.

Lawyer Thomas Demetrio said there will "probably" be a lawsuit, but his company is currently doing "due diligence".

He said the law stated that passengers could not be ejected from planes with unreasonable force.


United passenger's daughter: 'We were horrified'

At a Chicago news conference on Thursday, Mr Demetrio said he also wanted the case to prompt wider change at United and other airlines.

"For a long time, airlines, United in particular, have bullied us," he said.

"I conclude that based upon hundreds, literally hundreds, of tales of woe, of mistreatment, by United... here's what we want as a society: we want fairness in how people treat us, we want respect and we want dignity."

Dr Dao's daughter, Crystal Dao Pepper, said she had been "horrified, shocked and sickened" when she heard what happened to her father.

She described it as "a difficult time for her family" and said it "should never have happened to any human being".

She also said the family's "lives had been interrupted" and that their suffering had been "exacerbated" by seeing her father's forcible removal from the plane on video.

Passenger screams as he is pulled from plane

Dr Dao's lawyer said that the Kentucky physician had told him that being forcibly dragged from Flight 3411 was worse than the horrors he experienced in Vietnam.

"He said he left Vietnam in 1975 when Saigon fell. He was on a boat, he said he was terrified. He said that being dragged down the aisle was more horrifying and harrowing than what he experienced in leaving Vietnam."

Mr Demetrio said he did not believe race played a role in the Asian-American's removal from the plane.

Image: Oscar Munoz initially insisted the passenger's 'defiance' was to blame for his treatment

Dr Dao, who suffered significant concussion, has now been discharged from hospital.

United's chief executive Oscar Munoz apologised on Wednesday after initially defending the actions of his staff.

However, Dr Dao's lawyer said United had yet to make contact with either him or Dr Dao.

The Chicago City Council is currently investigating whether the airport officers who guard Chicago's two main airports had the legal authority to board the plane.

Three airport security officers have been put on leave following the incident.

:: Watch a special report on the United Airlines controversy on Sky News at 9.30am Friday.