Thanksgiving travel is set to be its heaviest in more than a decade.

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Get ready for delays if you're traveling this Thanksgiving. Holiday journeys could take up to three times as long as they normally would, according to AAA estimates.

Almost 51 million Americans – about 15 percent of the whole population – are expected to travel 50 miles or more from home to celebrate Thanksgiving this year, according to analysis from AAA and transportation analytics company INRIX. That's 3.3 percent higher than last year, and the largest number of travelers of since 2005.

Looking to miss the crowds? The worst time and day to travel depends on where you live, but Tuesday and Wednesday evenings look brutal across the board, according to INRIX estimates, since holiday travelers will get mixed up with everyday commuters.

All those extra travelers in the skies, on the roads, and on rails will mean fairly significant delays for many people, according to the report. Drivers will likely have it the worst, as AAA says 89 percent of all travelers — that's 45.5 million people — have a car trip on the agenda. Almost 4 million plan to fly, while another 1.48 million will use alternate modes of transportation including trains, buses and cruise ships.

Peak travel hours could make drives out of Chicago three times longer than normal, and road trips out of San Francisco, Los Angeles and Boston 2.5 times longer than usual. Airports nationwide promise to be bustling from Tuesday evening through Wednesday night.

As for where all those travelers are headed? Warm locales seem to be particularly popular, with Orlando, Florida, and Anaheim, California, topping AAA's list. New York City, Honolulu and Las Vegas round out the top five destinations.