It later came to light that passengers were removed so that the airline's own staff could take a seat. "You saw us at a bad moment", Munoz said.
"We're not going to put a law-enforcement official on to remove a booked, paid, seated passenger", Munoz said in an interview Wednesday with ABC. "We can't do that".
A United Airlines spokesperson told the agencies that the passengers "are receiving compensation for the cost of their tickets".
The officers' union contract prohibits the city from releasing their names, Pride said.
Chicago Aviation Commissioner Ginger Evans will also speak.
It was at least Munoz's fourth statement about the confrontation.More news: Dramatic end to historic Milan derby
After the video first emerged, he said the airline was reaching out to the man to "resolve this situation". On Monday, his tone turned defensive. Then, he described the passenger as "disruptive and belligerent" in an email, saying he "emphatically stands behind" the crew's actions.
But following days of sustained anger and an nearly $1 billion plunge in the company's share prices, he issued a third statement offering his "deepest apologies", and saying it was "never too late to do the right thing".
He pledged a full review of the circumstances, and said: "No one should be mistreated this way", ABC News reported.
Dao, 69, a resident of Elizabethtown, Kentucky, is a physician specializing in pulmonary conditions.
A spokeswoman for Dao's attorneys told BuzzFeed News it was "premature" to discuss anything about a potential lawsuit, but added that his lawyers would talk about the case during a news conference scheduled for Thursday morning. But other passengers on the plane can be heard arguing with authorities over Dao's treatment as the horror unfolds.
What is United Airlines' standard operating procedure when deciding to forcibly remove passengers, including those resulting from involuntary denied boarding?
He said the family "wants the world to know that they are very appreciative of the outpouring of prayers, concern and support they have received". He refused to leave. Fellow passengers captured footage of the officers seemingly slamming Dao against an armrest before dragging him along the floor down the aisle and off the plane.