transactions, e-mail or phone numbers that could be tied to terrorism. we recently talked to tsa chief david pakaski about the air marshals. >> we keep their presence covert. we don't want our adversaries to know they're on flights. >> reporter: but passengers aren't told they're on the quiet skies list or what happens to the information collected about them. some federal air marshals complain the program is a waste of money. the unions saying the american public would be better served if these marshals were instead assigned to airport screening and checking areas so active shooter events could be swiftly ended. civil libertarians are also concerned. >> it should go without saying government agents shouldn't be monitoring travelers without a good reason for doing so. >> reporter: tsa tells us that individuals can remain on this quiet skies list for up to three months after returning to the u.s. from a foreign airport. among those individuals who have already been surveilled and maybe didn't know it, an off-duty law enforcement officer, a business woman who