United Airlines flight UA858 from Shanghai to San Francisco erupted into chaos shortly after takeoff when a passenger went berserk.
As reported by the NY Post, the Boeing 777-300 had spent two hours in the air when the disturbance began. A video posted by a passenger on the same flight shows cabin crew intervening as the Chinese-speaking passenger allegedly began throwing all the documents in her seat pocket into the air, began screaming curse words, and hitting herself.
✈ A United Airlines flight from Shanghai to San Francisco was diverted to Tokyo on June 24 after a reported onboard dispute.
— Jiemian News (@jiemian_news) June 25, 2026
Chinese media said the dispute involved a passenger and the cabin crew.
Passengers said Japanese police boarded the plane after landing and escorted the… pic.twitter.com/5Smbg1SREI
Video posted by another passenger shows cabin staff intervening, with the witness reporting that the woman then accused flight attendants of trying to “oppress” her, and when they tried to intervene, she violently responded. As the witness explained:
“The crew captain [purser] tapped several times on her shoulder for her attention. In a startle reflex without even seeing who it was, she elbowed back.”
The situation worsened during food service, with the woman tossing food packaging onto the floor and screaming at other passengers.
Then, after air marshals intervened, the captain decided the only safe option was to redirect the flight to Tokyo Narita Airport. Cops were waiting for the flight, and the woman was escorted from the plane.
A lucky break for the passengers?
But then there was a strange twist: while conducting routine safety checks in Tokyo, a problem with the plane described as a “maintenance issue” was discovered, which had apparently gone unnoticed in Shanghai. This repair caused two hours of further delays before the flight was deemed safe enough to continue its trans-Pacific voyage, and it eventually touched down safely in San Francisco.
The exact nature of the problem with the plane discovered during its unscheduled stop-off is unknown.
Punishments for this kind of flight disruption are generally severe. For example, in 2021, Vyvianna M. Quinonez punched a flight attendant in the face on a Southwest Airlines flight, ending up with a 15-month sentence in federal prison, an order to pay the airline $26,000, and a further fine of $7,500.
However, if the passenger is deemed to be suffering a genuine mental health episode, there is some leniency. In May 2026, a 75-year-old male passenger made multiple attempts to breach the cockpit on a Chicago-to-Minneapolis flight, resulting in a diversion. Authorities described him as confused and in a mental health crisis after he was detained, and the FBI confirmed that no criminal charges were planned.
