As the TSA adds new airports with the service, carriers then sign up for the faster-screening program.
PreCheck allows eligible passengers to volunteer information to undergo faster screening, which generally includes being able to leave shoes, belts and light outerwear on, as well as keep their laptops and approved liquids in their cases. (Read more: Faster, Better Airport Security May Not Be Far Off)
The program is free and currently available to select frequent fliers at more than 25 U.S. airports. Participating airlines will either email an invitation to its members, or set up an opt-in page on their websites requiring members' frequent flier credentials for acceptance. The service is also available to members of the U.S. Customs and Border Protection trusted traveler program Global Entry.
I've opted in with both American Airlines and United and didn't have to provide any details beyond my frequent flier membership information. Other airlines participating in the program include Alaska and Delta. (Read more: Delta to Debut Outdoor 'Sky Deck' Terraces at Airport Lounges)
More than 7.5 million passengers have received expedited screening through PreCheck since the initiative began in October 2011, according to the TSA. For a full list of airlines and airports participating in the program, click here.