Depending on your vantage point, the main passenger terminal at Charleston International Airport has room to spare. Or not nearly enough.

VIP rooms rendered obsolete in the wake of 9/11 sit empty at the end of the airport's two concourses.

A sprawling, 49,000-square-foot federal inspection station that once checked in tens of thousands of U.S. service members and their families each year now is mostly unused.

On the other hand, airport security officials inspecting carry-on bags and patting down passengers spill out past the narrow concourse entrances because the building was never designed for them.

Flights are increasing. Passengers need more room to park. And the main runway is overdue for a makeover.

Those are just a few of the challenges facing the airport, a gateway to the Lowcountry designed nearly 30 years ago, long before terrorist threats were on the radar.

But over the next four years, big changes are coming to Charleston International, to the tune of about $200 million, to handle an increase in the number of passengers, upgrade areas of the 26-year-old terminal that are antiquated and accommodate changes in travel habits and security requirements in a post-9/11 world.

"We are having growing pains -- big time," said airport spokeswoman Becky Beaman.

In a separate project, the U.S. Air Force, which owns the runways and shares them with the airport, plans to rip out and repave the main, 9,000-foot landing strip sometime around the first of the year. It will be out of commission for about nine months at a cost to taxpayers of about $50 million. The shorter, secondary runway will handle all flights during that time.

Takeoff mode

At the independently managed airport terminal, the 324,000-square-foot building will be expanded by more than 25 percent.

The overhaul is overdue: Since 1985, when the building was constructed, security and technology have changed, and the building needs a makeover. The needed improvements will be phased in over the next four years.

"We can't just shut down," said Sue Stevens, director of airports for the Charleston County Aviation Authority, which owns and operates Charleston International. "We don't have the luxury like a school closing down to be repaired. We still have to serve our passengers during this process."

Preliminary plans, which are in the design stages, call for, among other proposals:

The first major project, starting in the second half of next year, will be adding on to the aircraft parking apron. That will provide more space to maneuver aircraft and allow some of the terminal expansion work to begin.

All told, the remake of the airport facilities alone will cost roughly $150 million, Stevens estimated.

"That's very, very preliminary," she said of the estimated price tag.

The money would come partially from the $4.50 passenger facility charge tacked on to ticket prices. The airport started collecting the fee, the maximum allowed by federal law, about 18 months ago to help prepare for the upcoming changes. It generates about $4.5 million a year and will fluctuate based on passenger volume.

Other funding most likely would come from federal grants and issuing bonds that the airport will repay out of its operating budget.

"No county tax dollars will be used to fund this," Stevens said.

She pointed out that, aside from the passenger fee, the improvements are not expected to affect fares charged by airlines.

"Ticket prices are based on supply and demand," she said.

To-do list

One change will be visible at the loading gates. As the concourses are extended, the number of gates will increase to 16 from 10. The number of passengers, which hit new highs in the spring after Southwest Airlines began serving Charleston, is expected to climb to more than 2 million by 2030. That's double the 2010 volume.

Expanding the concourse throats and reconfiguring the mostly unused federal inspection station will allow more passenger screening lanes to speed up lines at security checkpoints and provide more space for workers.

In the bowels of the airport, baggage screening will move to a more automated system. Currently, checked bags flow down the chutes and have to be hand-placed from carousels onto screening machines before being stacked on carts headed to airplane cargo holds. The new system will allow luggage to be automatically screened by skipping a handling step.

"It will allow us to grow smarter with the use of technology," Stevens said.

As for the current two baggage carousels where passengers pick up their luggage, they sometimes run constantly during peak travel times. "We need a little help there at certain times of the day or in case one of them breaks," she said. "Once the new belt is online, we will update the other two."

As the number of passengers waiting for flights past the security checkpoints increases, more concessionaires and more restrooms are needed.

"People's travel habits have changed," Stevens said. "They spend more time post-security than pre-security. Their 'dwell time' has gone up significantly. If you built this terminal today, you wouldn't build it like this."

As for parking, money is set aside in the current budget to help pave the way for 428 additional surface spaces in a wooded area near existing parking lots.

That, in turn, will make way for the doubling of the existing 1,200-space parking garage in the future.

For now, though, Stevens said all efforts will focus on upgrading the building.

"This is where the need is greatest," she said. "Parking is right behind it."