Austin-Bergstrom International Airport is bursting at the seams, and officials said an expansion is underway to accommodate 4 million additional passengers per year.

Jason Zielinski, senior public information specialist for the city of Austin Aviation Department, said a $350 million expansion project is scheduled to break ground in mid-2016 and be complete by late 2018.

“We’re seeing amazing growth,” Zielinski said. “The economy in Austin is strong; people are moving here. … We’re going to grow with it.”

ABIA is a one-terminal, 300,000-square-foot airport, according to the city. Zielinski said the terminal expansion will add 70,000 square feet—a 23 percent increase—and will include new waiting space in the gate areas, concessions, restrooms and more walkways. It will also add nine additional gates for domestic and international flights, he said.

The expansion will occur at the east end of the airport, near gates 1, 2 and 3, where the terminal comes to a dead end, Zielinski said. The airport already owns the property, and the expansion is part of ABIA’s master plan, he said.

ABIA’s capacity is 11 million passengers per year, Zielinski said. A November statistics report indicated the airport had already accommodated 10.8 million from January to November 2015. Officials predict it will surpass the 11 million mark when the December report is finalized, he said.

“We could use [the expansion] today,” he said.

Zielinski said the airport has experienced a 10 percent growth in the number of passengers since 2014, and it is one of the fastest-growing airports in the country.

The expansion process began in 2014 with approval from Austin City Council, contract negotiations for construction and design of the new space, he said.

“We have attracted a number of new nonstop flights [and] a number of new airlines,” Zielinski said. “We’re seeing sustained growth here. There’s a need. We know the airlines want to expand in Austin.”

Zielinski said in 2014, British Airways, a new airline to ABIA, began a nonstop service to London. In 2015, nonstop flights to Orlando, Miami, Toronto, Portland, St. Louis and Cincinnati, among others, began.

Airport projects are funded by grants, bonds and the Aviation Department’s fund for capital improvement projects. The capital fund includes airport revenue from parking, concessions, leases and passenger facility charges—a $4.50 fee included in the purchase of all tickets, according to the December 2015 Airport Construction Projects Audit.

“The airport doesn’t use any taxpayer dollars,” Zielinski said.

During construction ABIA may have to close one or two gates at a time, but it plans to use outdoor airstairs to accommodate passengers exiting or entering a plane when no gates are available, Zielinski said. ABIA does not anticipate the construction will severely disrupt passenger traffic, he said.