The amount of cargo going in and out of Spokane International Airport has risen dramatically so far this year, but most of that increase is just passing through, say representatives of the airport and a freight handler.

Spokane International Airport's traffic and operations report shows that total cargo through the first eight months of the year has climbed 22.9 percent compared with the year-earlier period.

Total cargo measures both inbound and outbound air freight. The airport reported 40,489 tons of freight were handled at the airport this year through August, up from 32,947 tons in the first eight months of 2011.

Todd Woodard says the increase is due largely to a consolidation of U.S. mail being handled under contract by the private carrier Atlanta-based United Parcel Service Inc.

Woodard says the acceleration in freight handled here started in the spring of 2011.

"We're just getting through a full year of reporting," he says.

For all of 2011, total cargo had also increased, but less dramatically, at 13.5 percent. Most of the increase came in the second half of the year. In the first half of 2011 the total cargo increase was up a modest 1.6 percent compared with the year-earlier period.

Jeff Pence, Spokane-based UPS supervisor, says the company is consolidating cargo here that's headed to Spokane and Portland.

"We've picked up quite a bit of postal and cargo volume that's being routed through Spokane," he says.

UPS dispatches up to four flights daily here, using Boeing 767 and Airbus A300 jets.

That number hasn't changed in the last few years since UPS started using the wide-body planes here, Pence says.

"We're turning the same amount of planes in a day," he says. "They are just heavier in volume."

Most of that freight is what he calls "through volume" that isn't originated in Spokane and doesn't stay here.

"A lot is from coming from back east," he says.

Pence says UPS doesn't handle postal freight that originates in Spokane, although he adds that he hears the Spokane contract for that is out for bid.

UPS leases 186,000 square feet of space at the airport, including a 4,000-square-foot cargo building and 105,000 square feet for aircraft parking, Woodard says. The rest of the space is for equipment and supply storage, he says.

The consolidation by UPS is unrelated to plans by the U.S. Postal Service to consolidate its mail and distribution operations here, says Ernie Swanson, Seattle-based spokesman for the service.

The Postal Service plans to close distribution centers in Pasco, Yakima, and Wenatchee, and move those operations to the Spokane distribution center, at 2928 S. Spotted Road, near Spokane International Airport.

The changes will take effect next year, he says, "probably February at the earliest."

Swanson says, however, that the consolidation likely will mean more postal-related freight will go through the airport next year.

The Postal Service often contracts with private-sector delivery services, he says.

"UPS and FedEx both fly a lot of first-class and priority U.S. mail," he says.

The Postal Service also provides some "last mile" delivery services for UPS, Swanson says.

"What's going outside of metropolitan areas often is passed on to us for delivery," he says. "We're competitors and also partners."

The increase in air freight here is bucking regional and national trends.

Sea-Tac International Airport reported total freight in the first eight months of the year edged up 0.5 percent compared with the first eight months of 2011, and the Tri-Cities Regional Airport reported total cargo declined 7.7 percent in the first eight months of 2012 compared with the year-earlier period.

According to the U.S. Department of Transportation, total U.S. air freight in the first half of 2012 was down 4.5 percent compared with the year-earlier period, although the department's Bureau of Transportation calculates it differently, factoring the distance that tons of freight are carried.

The increase in freight handled here, though, doesn't necessarily result in more revenue for the airport, Woodard says.

The airport's landing fees, for instance, are based on the aircraft weight capacity, not the weight of the goods carried. In the case of UPS, the number and size of its planes landing at the airport hasn't changed, he says.

Meantime, passenger numbers have declined somewhat in the first eight months of 2012.

The traffic operations report shows a total of 3.1 million passengers arriving and departing at the airport, down from 3.2 million in the year-earlier period.

Woodard says the modest drop in passenger traffic largely is due to a national reduction in capacity as airlines draw down their fleets due to high fuel prices.

"For the most part, passenger numbers are relatively even, and that points out how strong travel demand continues to be in our market," Woodard says.