Your eyes aren’t deceiving you in the luggage line: Seattle-Tacoma International Airport is busier than ever.

“If the numbers keep up, we will likely be the fastest-growing large airport in the country for the third year in a row,” Port of Seattle Commissioner John Creighton said. “We’re projecting that will put us in the top 10 U.S. busiest airports. We’re 13th now.”

The Port expects Sea-Tac to leapfrog Houston, Phoenix and Miami on that list.

Through September, the airport has seen more than 9 percent growth in the number of passengers. If that growth continues, more than 45 million people will have arrived or departed from the airport this year.

International travelers made up a large percentage of the increase. In September, the number of international passengers rose more than 14 percent.

Creighton said that growth has stressed Sea-Tac facilities.

“The international-arrivals facility was built for a peak of 1,200 passengers an hour, and it now sees 1,900 passengers an hour,” he said.

Numbers like those put the Port in a tough spot, as construction hasn’t caught up to passenger use.

“wher we have a lot of work to do is to catch up on the infrastructure needed to handle the volume. The commission has approved almost $2 billion in capital projects,” Creighton said, including a new international-arrival facility, a new center runway and expansion of the North Satellite used exclusively by Alaska Airline.

Congestion off the tarmacs is of concern too, Creighton said.

“There’s a lot of frustration about the airport drive. Planning for future growth in passenger traffic, we’re going to have to figure out how to get people to the airport efficiently,” he said.