A plane was forced to make an emergency landing after an unruly man began biting and even hitting fellow travellers.
Video footage shows how stunned passengers were asked to help restrain him as crew desperately tried to get him under control.
The mid-air drama unfolded as the JetBlue flight was flying over the US state of Utah.
Shocking footage shows the man, wearing a red T-shirt, lashing out at those sat next to him.
His arms flail in the air as he tries to strike those closest to him and screaming can be heard.
He started biting his seatmates before hitting others on the flight from Los Angeles to New York.
Doctors on board were asked to check on the man, but they were also attacked.
Another passenger intervened and held the man's arms behind his back until flight attendants could put restraints on him.
But in the footage the man can still be seen biting down in mid-air as if getting ready to strike again.
The man apparently knew the people he started biting on the Sunday flight, CBS News reported.
But the mid-air assault forced the pilots to divert and land in Las Vegas, where he was escorted off the aircraft by police.
The passenger who intervened, named only as Tom, said: “He was punching the passengers next to him, flailing his arms around, just acting irrational, crazy."
He added: “I grabbed his hands behind his back and held him there while the flight attendants put the restraints on him.
"At that point, he started yelling and tried to come towards the flight attendant, behind me, at the time. I really had a hell of a time keeping him in place there.”
JetBlue confirmed the man had been removed from the aircraft after the flight landed in Las Vegas. And in a statement it added: "Remaining customers resumed their scheduled flight to New York without further incident".
The flight arrived in New York hours late.
Las Vegas police told local media that the man was not charged.