After a London-bound plane was diverted to New York in a security scare that proved harmless, American Airlines is exploring how a flight attendant came to suspect a security breach, a spokesman said.
But he noted that the airline urges flight crews to act on any security concerns.
"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," said Tim Smith, a spokesman for the airline in Forth Worth, Texas.
The London Heathrow-bound flight was diverted to John F. Kennedy International Airport early Thursday. A flight attendant had become concerned that a passenger might not have gone through proper security screening before boarding at Los Angeles International Airport, 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. After talking to the man, flight crew members decided 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.
Authorities later questioned the man and determined he was not a threat, Transportation Security Administration spokesman Christopher White said.
"He was a regular passenger with a verified boarding pass, not an employee. There's nothing to indicate that he used employee transportation," White said.
The unplanned stop ended up exhausting the crew's allowed flight time, and passengers were transferred to other flights, Whitemon said.
The flight scare came amid renewed anxieties about potential terrorist attacks, and the TSA swiftly issued a statement saying the incident appeared to have "no nexus to terrorism."
Homeland Security Secretary Michael 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.
Associated Press Writers Tom Hays and Jennifer Peltz contributed to this report.