The number of aircraft gates at Charleston International is growing, but not by as much as previously planned.

The aging airport's terminal, in the throes of a $189 million expansion and upgrade, originally featured six new gates as part of the 28-year-old building's total makeover, which would have brought the total number of gates to 16.

But planners trimmed the number down to 15 to save money. How much? About $1 million, according to John Connell, director of engineering and planning at the Charleston County Aviation Authority.

All the new gates will be on Concourse B, which is being extended out into the apron area.

The original plan was to reposition airplanes at Concourse A to make room for a sixth gate to be added, but airport spokeswoman Becky Beaman said that plan was scrapped and officials now say planes can be repositioned to have two at one corner gate at the same time.

"We will have two positions that will be served by one gate," she said. "That will save us a lot of time and money in construction."

The gate at the far end of Concourse A on the left side will be able to serve two planes, Beaman said.

"The way it's positioned right now, we couldn't do that," she said. "There is enough space at the ramp. If we are careful how we place the planes, we can do it. That's a huge financial savings in building costs and buying another jet bridge."

In addition to the new gates, the terminal will add a third baggage carousel, consolidated security checkpoint, new rental car pavilion, an atrium dome and numerous other cosmetic and structural changes.

The work is expected to be completed in August | 2015.

Charleston International, the state's busiest airport, has seen a tremendous increase in passengers in recent years and could double passenger growth by 2030. In 2001, the airport handled about 1.6 million boarding and arriving passengers. That number is expected to climb to 2.6 million this year.

The 13-member Aviation Authority oversees the airport. It's chaired by Andy Savage, a local attorney.

Reach Warren L. Wise at 937-5524 or twitter.com/warrenlancewise.