Holiday travel: Busiest times to fly, drive this Christmas and New Year's

The Christmas and New Year's holiday period is expected to be the busiest on record for both air and road travel, according to AAA -- continuing this year's trend where every major travel period has set new records.

Here's what you need to know before you head to the airport or hit the highway:

Air travel

The Transportation Security Administration said it expects to screen nearly 40 million travelers from Dec. 19 to Jan. 2 -- a 6.2% increase from 2023.

The Federal Aviation Administration predicts Thursday, Dec. 19, will be the most crowded day to fly, followed by Friday, Dec. 27, and Friday, Dec. 20.

United is planning for its busiest holiday travel period ever, with 9.9 million passengers expected between Dec. 19 and Jan. 6. The airline said it's adding almost 500 more flights per day during its holiday travel period.

United said it anticipates its busiest days to be: Friday, Dec. 20; Friday, Dec. 27; and Saturday, Dec. 28.

American Airlines said Friday, Dec. 27, and Friday, Dec. 20, are expected to be its busiest and second-busiest days respectively during its holiday period, which runs from Dec. 18 to Jan. 6.

American said it'll serve more than 6.6 million bags of pretzels during its holiday travel period.

The cheapest days to fly are Christmas Eve and Christmas Day, according to Expedia. The busiest and most expensive days will be from Friday, Dec. 20, through Sunday, Dec. 22.

The most popular Christmas destinations in the U.S. are Las Vegas, New York City and Orlando, Florida, according to Hopper.

Airports in major cities are expected to be the most crowded in the mornings, between 8 a.m. and noon, according to Hopper.

Road travel

About 107 million people are forecast to drive to their holiday destinations between Dec. 21 and Jan. 1 -- approximately 2.5 million more people than last year, according to AAA.

The busiest days to pick up a rental car will be Friday, Dec. 20, and Saturday, Dec. 21, according to AAA.

If you're heading out the door on Dec. 20, the worst travel time is between 1 p.m. and 8 p.m. and the best time is before 11 a.m., according to analytics company INRIX. On Dec. 21, the worst time to be on the road is between 4 p.m. and 8 p.m.; the best time is before 2 p.m.

Traffic will be minimal on Christmas Eve, Christmas Day, New Year's Eve and New Year's Day, INRIX said.