The footage, filmed by another passenger on Wednesday, shows a man in an orange shirt, identified by police as Alexander Tung Cuu Le, running toward the attendant and assaulting him before stepping back.
Mr Le, a 33-year-old from Westminster, California, has since been charged with interference with flight crew members.
Authorities said the altercation began when Mr Le approached a flight attendant during beverage service, grabbed his shoulder and asked for coffee.
“After the flight attendant stepped back and put up a defensive posture, Le walked to the front of the airplane,” the US Attorney’s Office for the Central District of California said in a press release.
“Le then allegedly loitered near the first-class cabin and then sat in an unoccupied aisle near the wall dividing the first-class cabin and the main cabin of the aircraft.”
When a different flight attendant told Mr Le to return to his seat, he took up a “fighting stance” with closed fists, authorities said.
He then punched the crew member on their way to alert the captain.
Barrie Livingstone, who filmed the footage, told KTLA that Mr Le became angry when he was told that he couldn’t use the restroom in the front of the plane because he wasn’t seated in first class.
“Once he started screaming at him, the flight attendant just turned around and I think he was going to go and do something,” Mr Livingstone said of the altercation on American Airlines Flight 377. “But as he turned around and walked away, the guy jumped out of his seat, bolted down the [aisle], and punched him in the back. It was totally unprovoked.”
Another witness told ABC 7 Chicago that Mr Le had whispered “there are 10 killers on the plane” before the assault.
Four other passengers helped restrain the man, using zip ties on his hands and feet.
“It felt like you were very helpless and then every 10 minutes, he sort of had Tourette’s and would just lash out and start screaming and shouting about being the messiah and feeling misunderstood,” Mr Livingstone told KTLA.
The passenger was arrested by FBI agents and airport police upon landing.
“Acts of violence against our team members are not tolerated by American Airlines,” the airline said. “The individual involved in this incident will never be allowed to travel with us in the future, and we will work closely with law enforcement in their investigation.”
“We thank our crew for their quick action and professionalism to ensure the safety of their fellow team members and customers on board,” American Airlines added.
“If there wasn’t anyone who could’ve got up, it could have been much worse,” Mr Livingstone told KTLA.
According to the Federal Aviation Administration (FAA), there have been 1,973 reports of unruly passengers in 2022 as of 20 September. Investigations have been launched in 680 of those instances. The FAA site states that 468 enforcement action cases have been initiated.
There was a sharp rise in the number of incidents leading to investigations between 2020 and 2021. In 2020, there was 183 investigations started, according to the FAA, compared to 1099 investigations the following year.
There were 5,981 reports of unruly passengers last year, 70 per cent of which are reported to have been related to the rules regulating the use of facemasks, CNBC noted in April.