He has promised to review the airline's passenger-removal policy.
But if the passenger posed no threat and was not being disruptive, officers nearly certainly could have tried an approach other than dragging him out of his seat and down the aisle, including simply telling the airline to resolve the situation itself, experts said.
"We are not going to put a law enforcement official to take them off there", Munoz said. "We can't do that".
United recently announced that every passenger who was on flight 3411 last Sunday will now get their money back.
United Airlines spokeswoman Megan McCarthy said the passengers can take the compensation in cash, travel credits or miles.
Tomorrow the Chicago city council's aviation committee will also be making sure this doesn't happen again.
The City of Chicago has repeatedly declined requests to arm officers at O'Hare and Chicago Midway Airport, arguing that more people carrying guns would make the airports less secure not more, the Sun Times' Mark Brown wrote in an Op-Ed.
Munoz said United would be examining the way it compensates customers who volunteer to give up seats on overbooked planes, adding that it would likely not demand that seated passengers surrender their places.
Of course, it's good for some passengers, too: Of the 475,000 people who were bumped off flights on the 12 largest airlines a year ago, 91% did it voluntarily, agreeing to take cash or a travel voucher and a seat on a later departure.
The Sunday incident has grabbed headlines worldwide after being captured on a video that has gone viral.
Hours later on Monday, his tone turned defensive. He described the man as "disruptive and belligerent".
Then on Tuesday Munoz seemed to have another change of heart.
Lawyers acting for Dr David Dao have filed an emergency request with an IL court requiring the carrier to preserve video footage and other evidence relating to the incident, which sparked outrage on social media.
David Dao's lawyers on Wednesday made the first moves toward a lawsuit with an emergency filing in Cook County court.
There were so many ways that the airline could have handled this situation appropriately, "but to actually drag him out of his seat and to bloody him, is just absolutely outrageous", Chu said.
Likewise, the Chicago Aviation Department has said only that one of its employees who removed Dao did not follow proper procedures and has been placed on leave. "We apologize for the overbook situation".
The statement noted that "it is legal for airlines to involuntarily bump passengers when there are not enough volunteers" and that "it is the airline's responsibility to determine its own fair boarding priorities". Crew members asked an older man to leave, but he refused. Eventually, police officers were called to remove him. Other videos showed the man pacing around the plane's cabin with blood dripping from his mouth. But other passengers on the plane can be heard arguing with authorities over Dao's treatment as the horror unfolds. "This is wrong", "Look at what you did to him" and "Busted his lip".