By either plane, train or automobile, millions of Americans will brave record-breaking crowds this week to travel for US Thanksgiving.

US airlines are expecting nearly 30 million travellers to hit the skies during the Thanksgiving period, an all-time high.

"We expect this holiday season to be our busiest ever," the head of the Travel Security Administration (TSA) David Pekoske said this week.

Roads will offer little reprieve.

Most Thanksgiving travellers will drive to reach their turkey dinner, and the American Automobile Association (AAA) predicts just shy of 50m people will drive 50 miles or more for this year's holiday stretch.

This would be the third-highest travel numbers since AAA began tracking holiday travel in 2000 - marking an enthusiastic return to pre-pandemic levels.

The biggest travel days will be on Tuesday and Wednesday as well as the Sunday after Thanksgiving.

US Transportation Secretary Pete Buttigieg said at a news conference on Monday that his department had put preparations in place to avoid any major delays, including hiring more air traffic controllers and opening new air routes along the country's east coast.

But he warned of one major factor that could get in the way: "Mother Nature, of course, is the X factor in all of this," he said.

Mother Nature is expected to mostly cooperate over the next few days, even though parts of the country will see rain and snow.

As of Tuesday morning, heavy rain was moving across the East Coast, said Marc Chenard, a meteorologist with the National Weather Service.

In New York City, municipal agencies have issued warnings for heavy rains and strong winds.

Traveling by road on Tuesday will be "wet" across the east, Mr Chenard predicted, but the weather is unlikely to force any major flight delays.

The rainy weather is expected to clear by Thanksgiving day, he said. From there, some snowfall is predicted for parts of northern New England and portions of Montana, Wyoming and Idaho.

Otherwise, the weather this week is expected to be "quiet" Mr Chenard said, with temperatures hovering around typical seasonal levels.

"It should be a pretty nice Thanksgiving for most people," he said.