By Eliott C. McLaughlin

CNN

(CNN) -- The passenger forcefully removed from a United Airlines flight this week has a concussion and broken nose, his attorney told reporters Thursday, adding that the 69-year-old physician will file a lawsuit.

Already, attorneys have filed a chancery motion asking that all evidence in the case be preserved. David Dao's attorney, Thomas Demetrio, would not provide a timeline for filing the lawsuit other than to say he had two years to do so, and "I promise you it won't be that long."

"If you're going to eject a passenger, under no circumstances can it be done with unreasonable force or violence. That's the law," he said. "For a long time, airlines -- United, in particular -- have bullied us. ... We want respect and we want dignity. That's it. Not a big deal."

The lawsuit will be filed in Cook County Circuit Court in Illinois, the lawyer said, indicating it would target both the airline and the city of Chicago, whose Department of Aviation was involved in removing Dao from the plane.

Broken teeth, nose

Dao suffered "a significant concussion as a result of disembarking that plane," Demetrio said at a news conference in Chicago.

He also lost two front teeth, has a broken nose and incurred injuries to his sinuses, and will be "undergoing reconstructive surgery in that regard," Demetrio said.

The attorney further said that Dao had conveyed to him that "being dragged down the aisle was more horrifying and harrowing than what he experienced in Vietnam" when he was on a boat after the 1975 fall of Saigon.

Dao "has no interest in ever seeing an airplane again" and will likely take a car home to Kentucky, the attorney said, adding that his client has "absolutely zippo" memory of the incident.

Dao's daughter, Crystal Dao Pepper, also appeared at the news conference. She said her parents were returning home from vacation and making a connection in Chicago out of California. She described her dad as a "wonderful father" and "loving grandfather."

"My dad is healing right now, and that's all I have to say," she said.

'It wasn't even a matter of overbooking'

As millions saw via traditional and social media, Dao was aboard a Louisville, Kentucky-bound flight out of Chicago on Sunday night when Chicago aviation security officers forcefully pulled him from his seat and dragged him down the aisle of United Airlines Flight 3411.

His fellow passengers looked on, many of them filming the situation. United would say later it had to remove Dao to make room for four of its own employees, who needed to get to Louisville.

Demetrio seemed to take issue with the assertion the flight was overbooked.

"It wasn't even a matter of overbooking. It was a matter of at the last moment, four employes had to get to Louisville so they could get to work the next day," he said. "We take money from people, we let them sit on the airplane, seat belted. Are we really going to start taking them off then?

By Thursday, United conceded that the flight was not overbooked or oversold, despite its initial claim. It had no empty seats and four crew members needed to get on the plane to meet another flight in Louisville.

"There's really no word for it," said spokeswoman Megan McCarthy, who attributed the confusion to the airline's own understanding of what unfolded on the flight as it gathered additional facts.

Passengers back Dao

The airline offered compensation at first, but when that didn't convince enough passengers to take a later flight, it picked Dao randomly.

Passenger Jayse Anspach told CNN that Dao and his wife initially agreed to take a later flight but recanted upon learning that this flight wouldn't take off till Monday morning.

"He was very emphatic: 'I can't be late. I'm a doctor. I've got to be there tomorrow,' " Anspach recalled.

In video shot by Joya and Forest Cummings, who were sitting behind him, Dao repeatedly refuses to disembark, explaining he is a physician and must work in the morning. (Demetrio told reporters Thursday that Dao's wife is a doctor as well and also had patients to see Monday.)

The Cummingses said Dao was not belligerent and got only mildly upset when a second security officer arrived, demanding he leave the plane, they said. Dao never raised his voice, the couple said.

As security officers pry Dao from his seat, he screams. In video shot after the altercation, streaks of dry blood run from the Kentucky doctor's mouth. Passengers said he hit his head on an armrest.

Did CEO misspeak?

United Airlines CEO Oscar Munoz initially said Dao was belligerent, leaving security officers no choice but to employ force in removing him.

Munoz later struck a tone of contrition, telling ABC's "Good Morning America" on Wednesday that he felt "ashamed" over the incident and vowed never again to let law enforcement remove "a booked, paid, seated passenger" from a plane.

As for Munoz's earlier claim that Dao was at fault due to his belligerence, the CEO changed his heading, telling the morning show, "He can't be. He was a paying passenger sitting on our seat in our aircraft, and no one should be treated like that. Period."

Though Munoz said he attempted to contact the Dao and his wife, Demetrio said he feels Munoz "misspoke," adding that that didn't happen. As for Munoz's public apology, Demetrio said he accepted it, but it felt "staged."

"I'm not looking for a telephone conversation with Mr. Munoz," he said. "I'd rather he spend his time changing the culture of United Airlines."

United released a statement after Demetrio's news conference saying again that Munoz and United had "called Dr. Dao on numerous occasions to express our heartfelt and deepest apologies."

Officers' fate uncertain

Three Chicago Department of Aviation officers are on paid leave following the incident, and the airline's stock plummeted amid boycott threats.

The officers are supposed to serve as a first line of defense, by assessing and containing the scene before police arrive. The unarmed security officers receive about half the number of standard training hours as Chicago police officers, who are armed.

"If there's no imminent threat, if there's no fight, if there's no danger to the passengers in the plane, then the role of the ASOs is to stay there, contain the situation until CPD (Chicago Police Department) arrives," Jeff Redding, a deputy commissioner overseeing airport security, told the aviation committee of the Chicago City Council on Thursday.

"Our protocol is not to go on the plane if it's a customer service issue," he said.

At least one of the officers in the videos was wearing a jacket emblazoned with the word "police," which officials banned several months ago, City Aviation Commissioner Ginger Evans told the panel.

The fallout

In an email obtained by CNN, the airline told its passengers it was offering them $500 flight vouchers, but only if they agreed not to sue the company. A United representative later told CNN the airline did not mean to send emails with the "release of liability" language in them and that no passengers from Flight 3411 would have to agree to such terms to get their reimbursements.

The incident repulsed many United customers, some protesting by cutting up their United mileage cards.

United took a hit on the stock market. Shares in United Airlines slipped by 4% Tuesday, and the company's market value plummeted by $1 billion.

A Thursday statement said United wants to "make this right." It cited three changes it plans to make by month's end: never asking law enforcement to remove a passenger unless it's a security matter; reviewing policies on crew movement, oversold flights and incentivizing passengers to change flights; and improving training programs to ensure employees put customers first.

CNN's Emanuella Grinberg, Holly Yan, Rene Marsh, Deanna Hackney, Alanna Petroff, Jon Ostrower, Justin Lear, Gregory Wallace and Sheena Jones contributed to this report.