Haven't Left Yet? What You Need To Know Before Your Holiday Travel

The good news: you've missed the worst of it.

— -- Many may dub this week “the most wonderful time of the year,” but those taking to U.S. skies and roads may have a different opinion.

Travelers through U.S. airports can expect a small increase in passengers this holiday season, about 3 percent according to an industry trade group, Airlines for America.

Today, flight tracking site FlightAware says the most significant delays in the U.S. are due to thunderstorms in the east between Atlanta and New York.

Atlanta's Hartsfield-Jackson International Airport is seeing the worst of it, where some delays are as long as two hours.

The nationwide numbers as of 11:30 a.m. on Thursday: 1,596 delays and 172 cancellations - much of which are regional carriers. The cancellations are mostly due to planes not being where they are supposed to be as a result of some of the delays from yesterday, according to FlightAware.

On a typical day in the U.S. there are 4000 flight delays and around 200 cancellations.

According to Jana Tidwell of the American Automobile Association (AAA), nearly one in three Americans will travel for Christmas and New Year’s. More than 90 percent of those revelers will do so via our nation’s roadways.

The good news is those who are yet to leave for their destination have already skipped the worst of it.

Waze predicted Wednesday, Dec. 23 to be the worst day to travel this year.

Two days before Christmas in 2014, Waze recorded a 19.7 percent increase in accident alerts, 13.4 percent increase in traffic jams over a regular day.

The crowdsourcing navigation application predicted low volume of traffic on the morning of Dec. 24, but an increase in the afternoon. There is also a 14.04 percent increase in accident reports this day.

The analysis from Waze suggests people travel on the big day itself, Dec. 25, when road usage is below average.

For your return trip, you are better off taking to the roads on Monday. Sunday seems to be the worst day for drivers. Waze reports an increase of 87.7 percent in jam alerts, 13.7 percent in accidents alerts, 23.2 percent in hazard alerts and 32.6 percent in police alerts on this day.

Waze reports their methodology was analyzing 2014 app usage of millions of U.S. "Wazers" during the week of Christmas, as well as the two weeks prior and two weeks following the holiday for comparison.