If you travel frequently within the US or internationally, signing up for TSA PreCheck allows you to use dedicated lines at certain airports when you fly with approved airlines.
TSA PreCheck members are pre-approved as trusted travellers, so they don't require the extensive screening necessary for other people crossing the border.
TSA PreCheck Application
Applying for TSA PreCheck is in two stages. First, you submit your application to the government. The authorities review your application and perform background checks on you. This step is not mandatory but it is recommended.
You are then scheduled for an interview with an officer at a wide range of enrollment centers throughout the United States. If you have not pre-enrolled, you may have to return at another date.
If you are approved, you will be assigned a Known Traveller Number and be able to use TSA PreCheck lanes at participating airports, provided you are flying with an approved airline.