A flight from Los Angeles to London was diverted to New York early Thursday because a passenger was believed to have breached security.
A flight attendant on the American Airlines plane became concerned that the passenger might not have gone through proper security screening before boarding the London Heathrow Airport-bound flight at Los Angeles International Airport on Wednesday evening, said airline spokeswoman Sonja Whitemon.
The flight attendant had reported seeing the passenger ride to the terminal on an employee bus and bypass security, as employees are able to do, Whitemon said.
The incident appeared to have "no nexus to terrorism," the Transportation Security Administration said in a statement.
Authorities questioned the man at New York's Kennedy International Airport and determined he was not a threat, according to TSA Christopher White.
Homeland Security Secretary Michael Chertoff told CNN early Thursday that the passenger may have been an airline worker traveling for pleasure.
But White said later, "He was a regular passenger with a verified boarding pass, not an employee. There's nothing to indicate that he used employee transportation."
Flight crew members had decided, after talking to the man, that they needed to divert the plane to Kennedy to search the cabin and re-screen the 230 passengers, in keeping with standard security procedures, said Whitemon.
The plane landed at JFK at about 3:30 a.m., said Alan Hicks, a spokesman for the Port Authority of New York and New Jersey, which operates the airport.
The flight was later canceled because the unplanned stop ended up exhausting the crew's allowed flight time, and passengers were transferred to other flights, Whitemon said.
Tim Smith, a spokesman for American Airlines in Forth Worth, said the airline was interviewing the flight attendant to determine how she came to suspect that the man had skirted security or posed as an employee.
"We do fully support our crews on any security concern," Smith said. "We would always take the conservative route and get the incident or concern in front of the law enforcement people who are best equipped to handle it."
The flight scare came amid renewed anxieties about potential terrorist attacks. Chertoff said this week he had a "gut feeling" that the United States faced a heightened risk of attack this summer.
Numerous government officials have said they know of no specific, credible threat of a new attack on U.S. soil.