Alaska Airlines (copy) (copy)

Alaska Airlines will soon offer flights on six days of the week between Charleston and its home base in Seattle. File/Provided

The only cross-country, nonstop airline serving Charleston is nudging closer to offering daily flights year-round.

On June 11, Alaska Airlines will boost frequency of service between its home base in Seattle and the Lowcountry to six days a week, according to Helen Hill, Charleston's  chief tourism official.

"This is exciting news," said Hill, CEO of Explore Charleston and a member of the Charleston County Aviation Authority. "It shows that our air service is continuing to grow."

The carrier currently offers flights each day of the week except Tuesday and Saturday. The added route will leave Saturday as the only day of the week without service between the cities on each coast.

“We’re increasing our frequency of service to Charleston because we’ve been pleased with the performance of the flights in this time of year," said Alaska Airlines spokesman Ray Lane.

"We’ve seen steady growth since we began service to South Carolina," he added. "We’re excited we’re able to begin providing daily service during the midweek period, Monday through Friday.”

Alaska began offering nonstop flights between the Pacific Northwest and Southeast Atlantic — the East and West coast anchors to Boeing Co.'s commercial aircraft business — in 2015 with service on four days of the week. The airline added a fifth day of the week in March 2018.

"It's a not seasonal service," said Gary Edwards, a liaison between the region's tourism agency and Charleston International. "It's year-round."

When Alaska first announced the transcontinental flights four years ago, Edwards said the goal was eventually to grow it to a seven-day-a-week service.

"They have grown the market, and people have supported it," he said. "Boeing has done its part, too."

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Edwards also called Seattle "a stepping-off point for places in the Pacific Northwest and a gateway to transpacific travel."

The added flight will join the mix of two types of Boeing aircraft Alaska flies on the route. A 737-800 seats 159 passengers while the 737-900 can handle 178.

From Seattle, the five-and-a-half-hour trip leaves at 7:35 a.m. Pacific time and arrives in Charleston at 4:05 p.m. Eastern time.

The nearly six-hour return flight departs from Charleston at 5:05 p.m. local time and lands in Seattle at 8 p.m. Pacific time.

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