Yes, you can start the process for TSA PreCheck at many major airports in 2026, but you can rarely get it "instantly" for a flight leaving the same day. Most large hubs now feature IDEMIA or CLEAR-integrated enrollment centers where you can do your walk-in fingerprints and background check on the spot. However, the standard 2026 approval time is still 3 to 5 business days, meaning your Known Traveler Number (KTN) won't be active for your current trip. For a "day-of" solution, some 2026 travelers use the "PreCheck on the Fly" mobile units found at select airports like JFK or LAX. While the enrollment takes only 5 minutes, you still have to wait for the background check to clear. If you’re a 2026 traveler looking for immediate "expedited" entry without the KTN, your only real option is to pay for a CLEAR Plus membership, which verifies your identity instantly, though you'll still have to go through standard physical screening unless you already have PreCheck.