The TSA is expanding its "Pre-Check" program, hoping that by the end of the year, the program will be up and running at 28 of the nation's busiest airports.

FOX's Steve Centanni has details in our ongoing series on national security:

It's a way to expedite travel and make it safer.  The "Pre-Check" program allows frequent fliers to volunteer information about themselves prior to travelling.

Homeland Security Secretary Janet Napolitano says expanding the "Pre-Check" program is more than just speeding up travel, she adds it's part of a shift in how airport security operates.

(Napolitano) "In other words, when we are looking for that 'needle in a haystack,' we are also working with traveler programs to try to reduce the size of the haystack."

There are currently seven airports and more than 330,000 fliers participating in the "Pre-Check" program.  To learn more about it, go to www.TSA. gov.

In Washington, Steve Centanni, FOX News.