Australian federal MP Steve Ciobo was on board a US flight which two fighter jets were scrambled to escort after three passengers locked themselves in a toilet.
The two F-16 jets shadowed American Airlines Flight 34, which was flying from Los Angeles to New York, until it landed safely at New York's John F Kennedy International Airport at 4.10pm on Sunday (0610 AEST Monday), the Transportation Security Administration said in a statement.
The incident, which occurred amid heightened security on the 10th anniversary of the September 11 attacks, was not thought to be terrorism-related, a law enforcement official said.
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The passengers locked themselves in a toilet and were still inside when the plane landed, the official said.
Ciobo said nothing seemed amiss until he saw police lights on the runway after the plane landed.
The Queensland MP, who is the member for Moncrieff, looked out the window while still in flight and didn't notice anything.
"To be honest none of us suspected anything," said Ciobo, adding he got up at one point for the toilet and noticed a long line but didn't think twice and sat back down.
When the plane landed, he said, the airline workers told them to remain seated and that the authorities would meet the plane.
Everyone was quiet as air marshals got on board and headed for the back of the plane.
"To be honest, I think it's reassuring that there was such a great response from the authorities," he said.
"If there are people that are stupid enough to do those things on today of all days you wonder what's going on through their heads. But the fact that there were so many authorities there ... and that it all went so smoothly, I think they did a good job.
The fighter jets intercepted the flight about 160 kilometres west of New York and shadowed it until it landed, said John Cornelio, spokesman for the North American Aerospace Defence Command.
He described the measure as precautionary.
A "security concern" was brought to the airline's attention but the plane's captain never declared any sort of security threat and never requested law enforcement help, American Airlines spokesman Tim Smith said.
He said the crew used "normal procedures" to assess the circumstances and the plane landed as planned.
New York has been in a heightened state of security after federal officials received a credible but uncorroborated tip of a car bomb plot on the anniversary in either New York or Washington.
Law enforcement officials met the flight and would interview passengers, the TSA statement said.
