Department of Homeland Security officials say 100 percent of passengers traveling in the U.S. and its territories are now being checked against terrorist watchlists through the Transportation Security Administration's Secure Flight program - a major step in fulfilling a key 9/11 Commission recommendation.

Secure Flight enables TSA to screen passengers directly against government watchlists using passenger's names, their date of birth, and gender before a boarding pass is issued.

In addition to facilitating secure travel for all passengers, the program helps prevent the misidentification of passengers who have names similar to individuals on government watchlists.

Officials say 99 percent of passengers will be cleared by Secure Flight to print boarding passes at home by providing their date of birth, gender and name as it appears on the government ID they plan to use when traveling.