The Sioux Falls Regional Airport Authority voted unanimously Thursday to move ahead with a plan to renovate and expand the concourse so that it has 504 seats - nearly double the 272 now available in the upstairs area.
The expansion also will include a general remodel of the area as well as the addition of a restaurant/bar, gift area and desktop space for laptop users.
The authority put aside a plan that would have added a rotunda to the concourse and brought seating up to about 680.
The authority had been debating how much expansion was needed to ensure seating is adequate as the airport grows.
Kadrmas, Lee & Jackson engineering firm recently did an analysis of the Sioux Falls Regional Airport to better determine its future seating needs. The analysis looked at the airport's passenger activity and peak times, its boardings forecast and its existing concourse.
In 2008, the terminal had 367,800 boardings, said Steve Synhorst, an engineer with KLJ. By 2025, KLJ estimates that the airport will have about 500,000 boardings annually, he said.
Based on peak morning rush times having a 90 percent load factor, the airport would be using 400 seats during those times, Synhorst said.
"Expanding up to 504 seats, you're going to be in pretty good shape," he said.
Hal Wick, an authority commissioner, said that even as the airport grows and cuts down on leakage to other airports, the concourse should have enough seating in the future.
"You really have me feeling like we don't need a rotunda," Wick said, adding that commissioners should be able to put it off for another 10 to 15 years.
Koch Hazard Architects now will move forward in creating a final design plan for the project, which should be ready for a final vote in January, said Dan Letellier, executive director of the airport. He hopes the project will go out to bid by February or March.
Once the project gets started, it should take about 18 months to complete, said Chris Schiltz of Koch Hazard.
Reach Kelly Thurman at 331-2322.