AUSTIN (KXAN) -- Almost 40 million people are expected to take to the skies this holiday season, a 6.2% increase compared to travel figures last year, the Transportation Security Administration shared online Tuesday. The TSA is anticipating Dec. 20, Dec. 27 and Dec. 30 to be the busiest travel days this season. Those flying are advised to arrive at least two hours before their flight's boarding time to navigate parking or drop-off zones, check any luggage and undergo their security screenings. That arrival time is bumped up to three hours before international flights, per the TSA's 2024 travel tips resource guide. ICYMI: CLEAR debuts new verification technology at Austin airport The administration flagged travelers might encounter new screening technology at airports this year. Several airports use the second generation iteration of Credential Authentication Technology, or CAT-2 units. These verify a passenger's photo ID with their flight details and pre-screening status with an extra camera feature, the TSA said. Participation in that facial recognition technology is voluntary, the administration confirmed. Photos aren't stored or saved following positive identification, officials added. More details on holiday travel reminders, tips and tricks are available online.