That well-dressed gentlemen in 14A could be a insurance salesman from Cleveland like he says. Or, he could be part of a secretive US Transportation Security Administration (TSA) effort to monitor air travellers the agency considers suspicious.

The Washington Post reports that TSA only acknowledged the existence of the the “Quiet Skies” programme — which uses undercover federal air marshals to track specific passengers — after the Boston Globe reported on it in July 2018.

TSA officials say that travellers are targeted by Quiet Skies due to factors like past travel history, with marshals keeping note of inflight behaviour such as use of cellphones, sweating, or repeated use of the restroom.

“We are no different than the cop on the corner who is placed there because there is an increased possibility that something might happen,” TSA spokesperson James O. Gregory said. “When you’re in a tube at 30,000 feet… it makes sense to put someone there.”

Gregory said that travellers are not targeted based on race or religion. He did not reveal whether any arrests had been made as a result of the programme.

“Such surveillance not only makes no sense, it is a big waste of taxpayer money and raises a number of constitutional questions,” said Hugh Handeyside, senior staff attorney with the American Civil Liberties Union’s National Security Project.