A United Airlines flight from Shanghai, China, to New Jersey should have taken just 13 hours, but it took some folks three days to make that trip, after a firestorm of protests, threats, even violence.

United Flight 87 was scheduled to leave Shanghai Wednesday and bring 225 passengers to Newark Airport in New Jersey. The flight didn't land until Saturday morning after three days of cancellations, causing tense moments between passengers and United Airlines.

"You get the runaround by these airlines, said passenger Steve Borowka. "You're so powerless, just so humiliated and frustrated and you get so upset."

The flight was canceled twice because of maintenance on the Boeing 777, and a third delay came because the flight crew had been on duty too long. As passengers grew frustrated by miscommunications, tempers boiled over and a fist fight broke out.

"A group of people reached over the counter and ... grabbed [an airport counter agent] by the tie, and they pulled him physically across the counter and started slapping him," said passenger Pat Sinko, describing the violence at the scene after the flight was canceled for the second time.

Other passengers pulled the three irritated passengers off of the United counter agent, Sinko said.

The nightmare began, passengers say, after the first cancellation because of maintenance. The airline put all the passengers up in hotels. Thursday arrived, and so did a second setback: The replacement generator, which has to be shipped from the U.S., didn't make it to China in time. On Friday, United Flight 87 passengers were promised they would leave, even if travelers on another flight had to be bumped.

That's when the pilot of the flight told the passengers the original plane had been fixed and was located at another gate. One Chinese passenger refused to go to the other gate and organized a mini revolt to block newly arriving passengers from getting on the plane.

"He was like if we're not getting on that plane, nobody is getting on that plane," said Borowka.

A video taken at the gate shows the pilot pleading with passengers to go to the other location where another plane was waiting for them.

"That is the only way we're going to get out of here. ... My crew, the other crew, we want to go as much as you do," the pilot said. "I can tell you the alternative is, if we don't have cooperation boarding here, these planes may leave empty."

Eventually, Borowka and the other passengers were ushered to the other gate and began boarding their new plane, and were dealt a final humiliating blow: The flight crew had been on duty too long. The passengers were bumped off the plane again.

"Some of the Chinese people wouldn't get off the plane. They were protesting, and the other people were trying to break down the door trying to get back in the airport," said Sinko.

Passengers also say they couldn't get to their luggage, some of which was unceremoniously dumped off carousels.

After three days of cancellations, the plane finally landed in Newark on Saturday morning, bringing the chaotic ordeal to an end.

United said it would cover passengers' expenses during the delay and offer each customer a full refund, as well as US$1,000 off future travel on the airline.