Nearly 1.8 million passengers are expected to flow through the world’s busiest airport over the Thanksgiving travel period, up 3.3 percent from a year ago.

“It’s a good sign that the economy is doing a little bit better,” said Hartsfield-Jackson International Airport general manager Louis Miller. “People are moving forward.”

Industry group Airlines for America also expects a national increase in passengers flying during the Thanksgiving period, projecting 1.5 percent growth.

Planes are expected to be packed on the busiest days, averaging more than 85 percent full. For the Atlanta airport, the Saturday and Sunday after Thanksgiving will be busiest, with 261,893 and 277,229 passengers are forecast, respectively.

Those driving to the airport should also expect construction work on roads surrounding the domestic terminal.

The Transportation Security Administration advised travelers to allow extra time to get through security, with more than 60,000 passengers a day passing through checkpoints at Hartsfield-Jackson over the holiday period.

Thanksgiving is among the busiest travel times of the year at airports around the country. Americans have spent $14 billion on “obligatory” Thanksgiving travel in the past year, including for this Thanksgiving, according to Hotwire.com.

But according to AAA, overall Thanksgiving travel in Georgia is down slightly from last year, including those driving. The auto club tied the decline to “weakened consumer sentiment tied to economic uncertainty and the government shutdown” — but said travel volumes are still well above 2008-09 recessionary levels.

And traffic at Hartsfield-Jackson is expected to be down on the Monday, Tuesday and Wednesday before Thanksgiving compared to last year. Miller attributed that to a decline in business travel. Southwest Airlines has been cutting flights as it dismantles AirTran’s Atlanta hub to focus less on connecting traffic.