To add TSA PreCheck® to your Air Canada flights, ensure your Known Traveler Number (KTN) is included when booking your ticket. You can do this through Air Canada's website or by contacting their customer service. Once your KTN is linked to your reservation, you'll enjoy expedited security screening at participating US airports. Remember, TSA PreCheck® is available for eligible passengers, so make sure you've enrolled in the program beforehand through the Transportation Security Administration (TSA) to enjoy smoother travels.