More people are traveling for Thanksgiving this year than they have in nearly a decade, and airports are bracing for a record-breaking number of passengers Wednesday.

More than 48 million Americans are expected to travel 50 miles or more for the holiday, an increase of about a million from last year, and the highest number since pre-recession levels in 2007, according to AAA.

Of those, a record 3.6 million are expected to be flying, 43 million driving, and another 750,000 will be taking trains to their Thanksgiving destinations.

Airports were already filling up with long lines early Wednesday morning.

"Have patience," passenger Frank Hagen warned other flyers from Miami International Airport, where he spoke to NBC Miami as lines grew.

Despite snow and gusty winds in the Northeast, upstate New York, northern Pennsylvania, and parts of the Midwest earlier in the week, weather across much of the U.S. was in travelers' favor Wednesday morning. Still, by Wednesday afternoon, over 600 flights across the country had been delayed, according to FlightAware.com, and 34 flights were canceled.

The better economy, cheaper airfares, plus gas prices that are at their second lowest in 10 years, are contributing to the uptick in travel. This year's most popular destinations are Las Vegas, San Francisco, San Diego, Orlando, and New York City, according to bookings on AAA's website.

In New York — where security is always tight for the famed Macy's Thanksgiving Day Parade — counterterrorism officials and the NYPD were prepping for the holiday: Every cross-street along the parade route will be blocked off for the first time as more than 3,000 police officers stand guard, reported NBC New York. The extra measures follow the Bastille Day truck attack at a parade in Nice, France, that killed 84.

The busiest travel hubs this year are expected to be Atlanta, LAX, Chicago's O'Hare, Dallas-Fort Worth, and New York's JFK airports.

For drivers hoping to avoid gridlock, it's best to hit the road early: According to Google Trends and Maps, the worst time to leave is 3 p.m. on Wednesday, and the worst time to return is 4 p.m. on Saturday. Thanksgiving Day itself is considered one of the least busy days to travel.