An expanded version of America's annual Thanksgiving travel saga has begun with gas prices low and terrorism fears high.

An estimated 46.9 million Americans are expected to take a car, plane, bus or train at least 50 miles from home over the long holiday weekend, according to the motoring organization AAA. That would be an increase of more than 300,000 people over last year, and the most travelers since 2007.

Similar scenes are anticipated Wednesday at Tampa International Airport and on the Bay area interstates.

Among the reasons given for the increase: an improving economy and the cheapest gasoline for this time of year since 2008.

With prices falling for 17 consecutive days, drivers are getting a total of 15 cent savings per gallon in many parts of the U.S. Gas prices in Florida are averaging $2.09 a gallon.

And the drop isn’t expected to stop.

The national average retail price of gas is expected to fall below $2 per gallon by the Christmas holiday. Many stations around the Bay area are already selling gas for less than $2 per gallon.

Meanwhile, millions more are taking to the air to travel as part of their holiday.

At Tampa International Airport, officials say they’ve made some changes amid ongoing construction to accommodate holiday travelers as they’re entering and leaving the airport.

Drivers will not be able to circle the main terminal anymore while waiting to pick people up at curbside.  

Now, they will have to circle the entire airport. Airport officials say the best idea is to use the Cell Phone Waiting or Short Term Parking while waiting for guests.

Though there have been no changes to the nation's terror alert status, the recent attacks in Paris, West Africa and elsewhere prompted the State Department to warn American travelers about the risks overseas.

On Tuesday, the head of the Transportation Security Administration, Peter Neffenger, boasted that the U.S. has the world's best aviation security and assured the public that TSA is "taking every measure to protect the millions of air travelers in the coming weeks."

Information from the Associated Press was used in this report.