Meantime, two more airport police officers involved in the passenger removal debacle have been placed on leave.
The Aviation Department's roughly 300 officers guard the city's two main airports but are not part of the regular Chicago police force, receive less training and can not carry guns inside the terminals. CDA said it will not release the names of the officers.
Dao was one of four passengers asked to leave an overbooked United Airlines flight departing from Chicago to Kentucky on Sunday. As of Tuesday, Dr Dao was still in a Chicago hospital recovering from his injuries, his lawyer said.
Munoz repeated his apology to David Dao, his family and the other passengers who witnessed him being taken off the flight. "This can never, will never happen again", he said.
David Dao, the physician who was forcibly removed from a United flight, has filed court papers seeking to preserve and protect records related to the now infamous flight on Sunday night.
On Wednesday, Munoz said he did not blame the passenger, and added that his initial comments "fell short" of what he felt.
Meanwhile, New Jersey Governor Chris Christie condemned United Air Lines for directing law enforcement officers to physically drag off a passenger who reserved a seat and paid his ticket.
United Airlines issued three statements on the incident, at first suggesting Dr Dao was partly responsible and labelling him "disruptive and belligerent" in a leaked email. But he did an about-face days later, saying the doctor did nothing wrong. That's something that I've learned from. "No one should be treated that way". "We are not going to put a law enforcement official to take them off the aircraft". "I was hired to make United better, and that's what we'll do".
In his interview, Munoz said he has unsuccessfully tried to reach the passenger to apologize directly.
Beset with a continuing public relations nightmare, United Airlines has confirmed that it is compensating all passengers on now-infamous Flight 3411. United is offering compensation in the form that the passenger wants. United customers at O'Hare reacted Wednesday to the promised changes. They care about their customers.
"They all have an incredible amount of common sense, and this issue could have been solved by that".
"The Department remains committed to ensuring that airlines comply with consumer protection regulations and will not speculate during the review process on this matter", it said. She "absolutely" thinks the problem can be fixed.
In this Thursday, June 2, 2016, file photo, United Airlines CEO Oscar Munoz waits to be interviewed, in NY, during a presentation of the carrier's new Polaris service, a new business class product that will become available on trans-Atlantic flights.