Charleston International Airport parking

Charleston International Airport officials continue to work toward adding a second parking deck to handle the growing passenger demand at the state's busiest airfield. File/Jonathan Sheppard/Charleston County Aviation Authority

Rapid passenger growth is forcing Charleston International Airport to plot more expansion plans.

A new parking garage is on the way, a third wing is not that far off and more ticket counter space could soon be coming. 

In January, construction will begin on a new 3,005-space parking deck behind the existing garage to make room for the airport's increasingly cramped auto lots, especially during holiday travel periods.

And while the prospect of adding a third wing to the state's busiest terminal has been broached before, officials have never quite pinpointed a possible construction timeframe.

Now, deputy director Hernan Pena believes six new gates will be needed by 2025 or 2026. "Concourse C" would rise near the site of an existing rental car lot at the far end side of the terminal.

"As growth continues, we are going to need another concourse," Pena said. "We know growth is coming, and we want to be vigilant with what's coming in the future."

The five-level parking garage is expected to cost between $110 million and $120 million, but the exact price tag has not been determined, according to airport CEO Paul Campbell. The Charleston County Aviation Authority board is expected to see the final design in September.

Construction on the new deck is projected to be completed in November 2020, just ahead of the holiday travel season.

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Construction on a new parking deck at Charleston International Airport will begin in January behind the existing parking garage. The 3005-space parking facility will be built in the right front foreground of this photo. Boeing Co.'s aircraft assembly plant is in the distance. Leroy Burnell/Staff

The future parking deck's location behind the existing garage would leave room for a third garage, if needed, to meet demand.

Work has begun on preparing remote lots for vehicles that will be displaced in the surface lot once construction begins.

The airport projects a cost of $1.2 million during its next spending cycle, which starts in July, to shuttle passengers from outlying surface parking areas to the terminal once construction begins.

Also coming up, possibly as early as next month, will be a plan to expand the airport's ticket counter space.

The addition of Allegiant and Frontier airlines this year has filled up the terminal's ticketing area, where Alaska, American, Delta, JetBlue, Southwest and United already operate.

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"Our ticketing hall is really thickening up," Pena said. "As growth continues, it will continue to put pressure here."

Campbell pointed out the airport can shoehorn another airline into the lineup if necessary.

"But it will be difficult," he said.

Charleston International ferried 3.9 million passengers coming and going through its terminal last year. Campbell believes the number will reach 4.4 million this year.

Several airlines are adding seasonal flights to new destinations during the spring and summer travel seasons, helping to boost passenger counts.

Charleston International now provides nonstop service to 28 airports in 24 cities and averages about 160 flights a day at this time of year.

Reach Warren Wise at 843-937-5524. Follow him on Twitter @warrenlancewise.