There were no men with knives onboard an aircraft at New York's JFK airport.
Sen. Joseph Biden said the travelers were found to have no connection to the attacks, according to the senator's chief of staff, Alan Hoffman.
Biden said the arrests were based on suspicions that they were linked to the attacks, but those connections turned out to be "totally, totally coincidental."
One man was arrested because he was belligerent, while the others were merely detained and questioned, Hoffman added. A source with the Senate Foreign Relations Committee, which Biden heads, said all but one of the group had been released.
The three New York area airports Kennedy, La Guardia and Newark were closed Friday morning, but reopened about noontime.
The airline industry is on the alert for 52 people who authorities have put on a list as wanted for questioning.
Concerns are also being driven by what one official, speaking anonymously to the AP, says is fresh intelligence which "suggests we haven't seen the end of this current threat." The official also cited concern that terrorists may strike in a different manner now that airport security has been tightened.
Authorities at Pearson International Airport in Toronto reportedly have detained a man carrying a bizarre photo of himself in a flight crew uniform against a fake backdrop of the World Trade Center.
According to The Globe and Mail, the man was refused admission to Canada and is being questioned.
Sources say the man, who said he is an aircraft maintenance engineer in Gaza, was supposed to have arrived at a U.S. destination just days before Tuesday's terrorist attacks, but was delayed for some unidentified reason.
The newspaper reported the man was also carrying aviation paraphernalia but it has not yet been determined whether there is any connection to the hijackings and crashes in the U.S.
The FBI was already investigating whether an altercation at Kennedy Airport on Tuesday was linked to the World Trade Center explosion, a law enforcement source told The Associated Press on Thursday.
The Tuesday incident occurred about 9 a.m. the same time two hijacked jet airliners crashed into the World Trade Center towers, toppling the two 110-story buildings. The source said the FBI is investigating whether the incident may have been an aborted hijacking attempt.
After the plane was boarded, United Airlines officials told passengers that United Airlines Flight 23, bound for Los Angeles, had been cancelled.
Three males traveling refused to disembark. The argument with a member of the flight crew became so heated that the crew member called airport security.
But before security arrived, the men had vanished, said the source, who spoke on the condition of anonymity.
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