BOSTON — Amid renewed anxiety about air travel and tough new regulations about what passengers may bring on planes, at least seven U.S. flights were involved in security incidents Friday. In one case, a stick of dynamite was found to have been aboard a flight.
The series of events, safety consultants and others said, reflected heightened emotions and appropriately tightened security in the wake of an alleged plot to blow up transatlantic airliners that was thwarted this month by British authorities.
"I think it's a combination of both," said Douglas Laird, a Reno-based consultant to the airline industry and former longtime security director for Northwest Airlines. "I think there is a heightened awareness of what happened in London, and that causes some people to overreact."
In what may have been Friday's most serious incident, authorities said a college student's checked luggage on a Continental Airlines flight from Argentina was found to contain a stick of dynamite after it landed in Houston en route to Newark, N.J.
A bomb-sniffing dog at the international-arrivals area at George Bush Intercontinental Airport detected an explosive substance in a suitcase. It belonged to a man who told Houston authorities that he worked in mining and often handled explosives.
Howard McFarland Fish, 21, was in federal custody. His actions were determined not to be terrorism-related, according to Immigration and Customs Enforcement.
The flight continued to Newark without Fish or his baggage and was swept again for explosives upon landing, officials said.
Three U.S. aircraft -- from American Airlines, U.S. Airways and Continental Airlines -- made emergency landings Friday.
A Transportation Security Administration spokesman said American Airlines Flight 55, bound for Chicago from Manchester, England, was diverted to Bangor, Maine, because of "a reported threat to the aircraft while it was en route."
FBI spokeswoman Gail Marcinkiewicz in Boston said she was unable to specify the nature of the alleged threat but confirmed that the FBI was participating in an investigation in Bangor. "We aren't going to give out any of the details," she said. "Until all of it is taken care of, we can't comment."
Marcinkiewicz said the plane was diverted to Bangor because it is the northernmost major airport in the U.S. She said the plane carrying 188 passengers landed at about 12:45 p.m. Friday.
A TSA spokesman said that "given the current threat level, the agency, in conjunction with other federal authorities, took prudent action to ensure the security of passengers and crew." The spokesman said TSA dogs searched the plane.
Also Friday, a U.S. Airways jet bound for Charlotte, N.C., from Phoenix made a forced landing in Oklahoma City after a federal air marshal reportedly subdued an unruly passenger. Authorities declined to give details.
And after the crew of Continental Flight 2258 discovered a missing panel in a lavatory, the plane bound for Bakersfield from Corpus Christi, Texas, was diverted to El Paso, according to the TSA.
The plane carrying 50 passengers was held for about four hours before officials determined there was no danger. "The passengers were interviewed, and the aircraft was thoroughly inspected with all the tools at our disposal, including canine teams," said Pat Abeln, director of aviation at El Paso International Airport. "At the end of the day, this was a precautionary event that turned out to be a nonevent."
In three other incidents, a utility knife was found aboard a parked U.S. Airways plane in Connecticut, takeoff of a United Airlines flight in Chicago was delayed after concern about a possible bomb, and in Ireland, an Aer Lingus plane from the U.S. was evacuated after it landed.
Authorities in Hartford, Conn., boarded U.S. Airways Flight 554 from Philadelphia after a passenger found a utility knife on a vacant seat. No arrests were made, and no threats issued, state police said. Police and the FBI were investigating whether the knife had been left by a worker or by a passenger.
At Chicago's O'Hare Airport, a flight attendant aboard United Flight 686 overheard a minor say he had a bomb and alerted the pilot, who taxied to a secure part of the airport. The minor's mother and the minor were removed from the plane, and it was searched, an FBI official said. After bomb-sniffing dogs found no explosives, the flight, which was on a layover between Portland, Ore., and New York's LaGuardia Airport, was allowed to continue.
And in Ireland, an Aer Lingus plane from New York was evacuated at Shannon Airport after police received a call early Friday claiming that "some sort of device" was on board. Police found nothing suspicious, Aer Lingus officials said, and the plane returned to service.
Aviation security has increased dramatically since British intelligence services announced Aug. 10 that they had broken up a plan to destroy transatlantic airliners with liquid explosives. Two dozen people were arrested, four of whom have been released.