More than 1.6 million passengers are expected to pass through Hartsfield-Jackson International Airport over the long Memorial Day weekend, kicking off the busy summer travel season.

Hartsfield-Jackson forecasts weekend traffic over the holiday travel period running from Thursday through Tuesday will be up 3 percent this year compared with 2012.

But nationally, AAA Travel said it expects Memorial Day air travel to be down, while travel by automobile will be up. The auto club said in Georgia, about 1 million will travel for the holiday, about 9 out of 10 of them going by car.

Meanwhile, national airline industry group Airlines for America said it expects travel on U.S. airlines for the full summer to be up 1 percent from 2012, with a record number of international passengers. The group said the busiest air travel days are Thursdays and Fridays from mid-June through early August.