Two of the passengers speak to reporters after they deplaned

In this story:

• Alcohol a factor
• Two men arrested in London incident

NORFOLK, Virginia (CNN) -- A charter jet enroute to Jamaica from London made an unscheduled stop in Virginia Sunday after fighting broke out among passengers, an airline spokesman said.

Twelve people -- six English and Irish couples -- were removed from the Boeing 767 in Norfolk, Virginia, said David Parsons of Airtours International.

Although the rowdy passengers were questioned by airport police and FBI agents, none of the travelers face criminal charges.

"We rather think it was some personal interplay between the people, who perhaps knew each other," Parsons said. "Certainly they were fighting and uncontrollable, and clearly the calming techniques which we teach our cabin crews didn't work. Diversion was the only option."

Airlines in Britain have reported a 400 percent increase in air rage incidents over the last three years, and some officials fear that an out-of-control passenger will one day bring down a packed jet.

Last week, police and airlines at Britain's third-busiest airport, in Manchester, launched a get-tough campaign to fight the growing menace of "air rage" passengers who lose control during flights.

In the latest incident, a spokesman for the Norfolk airport said alcohol was a factor in the brawl. "About 12 passengers consumed quite a fair amount of alcohol and became somewhat unruly," airport spokesman Wayne Shank said.

The trouble apparently began with shouting and a drink thrown by one passenger at another traveler.

"After thorough investigation, it was determined that there had been no direct interference with the flight crew and the local U.S. attorney declined to prosecute," Shank said. Interfering with a flight crew is a federal charge, he said.

Patty Schlosser, an FBI spokeswoman in Norfolk, said the passengers made their own arrangements to leave.

Shank said the group had calmed down by the time the plane landed.

"I think the fact that the pilot put the airplane on the ground and allowed local police aboard was in and of itself a sobering experience," Shank said. "They were all somewhat apologetic."

The other passengers continued on to Jamaica.

Parsons said that "the recent high profile of bad behavior among passengers has meant that no airline is prepared to accept this sort of behavior."

In a separate incident, two men were arrested at London's Heathrow airport Sunday night after a stewardess on a Casablanca-to-London flight told police she had been groped.

Police boarded the Royal Air Maroc Boeing 737 jet just after it landed to arrest the men, who were later released after being given a formal warning for common assault.

The Associated Press and Reuters contributed to this report.