Man dragged off United flight plans to sue: lawyers

David Dao was released from the hospital overnight and was at a "secure location," attorney Thomas Demetrio said at a news conference during which a member of Dao's family spoke out for the first time.

Meanwhile, United remained under the spotlight as representatives of the carrier faced tough questioning at a city council hearing in Chicago, where the airline is headquartered and where the incident occurred.

Dao's lawyers filed a petition in court requesting that the city, which operates O'Hare International Airport, and United Airlines preserve evidence related to the incident. They also said a lawsuit was forthcoming.

"This lawsuit, among other things, hopefully, will create a not just national discussion, but international discussion, on how we're going to be treated going forward," Demetrio said.

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

Dao 'healing

Online video of airport security officers dragging Dao off a packed flight Sunday sparked worldwide outrage. He screamed as officers pulled him from his seat, and was bloodied by the altercation.

The 69-year-old doctor's lawyers said he also suffered injury to his sinuses and lost two front teeth.

"My dad is healing right now," said Crystal Dao Pepper, 33, one of Dao's five children.

"We were completely horrified and shocked at what had happened to my father," she said.

In response, United Airlines released a statement reiterating apologies from earlier in the week.

"We continue to express our sincerest apology to Dr. Dao. We cannot stress enough that we remain steadfast in our commitment to make this right," the statement said.

The airline also said that it would no longer ask law enforcement to remove a passenger from a flight unless it is a matter of safety and security.

United's apologies have not quelled a torrent of criticism, especially since those apologies came days after the incident -- and after its initial statements appeared at least in part to blame Dao.