Flight 976 had departed New York’s John F. Kennedy International Airport around 9:30 p.m., Wednesday, Oct. 27, and was headed to John Wayne Airport in Orange County, California, but was diverted to Denver because of the incident, the airline said in a statement.
The aircraft landed safely and taxied to the gate where law enforcement removed and apprehended the passenger, the airline said.
American Airlines did not provide details or the flight attendant's condition.
But passengers said the man allegedly punched a female flight attendant twice in the face in a dispute over masks according to witnesses.
"We are outraged by the reports of what took place on board. Acts of violence against our team members will not be tolerated by American Airlines, the airline said in a statement. "We have engaged local law enforcement and the FBI and we are working with them to ensure they have all the information they need."
The airline went on to say that the unidentified individual involved in the incident will never be allowed to travel with American Airlines in the future, "but we will not be satisfied until he has been prosecuted to the full extent of the law.
"This behavior must stop, and aggressive enforcement and prosecution of the law is the best deterrent," they added.
The passenger's identity has not been released, and no details were immediately available about charges.
A passenger on the flight identified as Mackenzie Rose posted a photo of the man on Twitter.
Rose said the reason for the attack was the man didn't want to wear a mask.
The airline thanked the crew for their quick action to ensure the safety of the customers and team members.
"Our thoughts are with our injured flight attendant and ensuring that she and her fellow crew members have the support they need at this time," they added.
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