After a free fall worthy of Black Friday, Pittsburgh International Airport may have finally bottomed out.

For the second month in a row, the airport posted a rare increase in passenger traffic, perhaps a sign that better days are ahead after nearly a decade of cutbacks by dominant carrier US Airways.

Traffic was up 1.5 percent in May compared with May 2009, according to the Allegheny County Airport Authority. That followed a three-tenths of 1 percent increase in April.

As modest as the bumps are, they mark the first time the airport has managed to achieve consecutive gains in traffic since the spring of 2007, when it put together three straight months of increases before watching passenger volumes plummet again for 33 months.

Traffic has been plunging since the Sept. 11, 2001, terrorist attacks, after which US Airways started a series of flight cutbacks in Pittsburgh that have stretched over much of the past nine years.

Airport Authority Executive Director Bradley Penrod attributed a "significant piece" of the May increase to the start of the busy summer travel season. In May 2009, the country was in the grip of a deep recession, which deadened air travel.

But Mr. Penrod also believes that the gain is the result of increases in the airport's local traffic the last few years and the airport's ability to contain costs and provide good customer service.

"[The airlines] are seeing some very positive signs and efforts in Pittsburgh," he said. "We've established quite a track record on how we do things, and the carriers recognize that, and they appreciate it."

Mr. Penrod predicted traffic would continue to rise through the fall. As the economy improves, it should generate more business travel, and autumn is a peak time for that, he said.

One good sign, he added, is that load factors on planes out of Pittsburgh are averaging 81 percent, about half a percentage point higher than last year. Mr. Penrod said airlines typically look to add larger planes or more service when load factors reach 80 percent.

"I think we're in a very positive position right now," he said.

Nine airlines posted gains in May, led by AirTran Airways, at 63.5 percent. JetBlue Airways reported an 18.2 percent increase, and United, 11.4 percent, which Mr. Penrod tied mainly to the carrier's nonstop flights to San Francisco and Los Angeles.

Despite the improvement, traffic volume isn't close to what it was in 2001, the heyday of the US Airways hub in Pittsburgh. That May, almost 1.9 million passengers boarded and got off airplanes, most of them making connections. This past May, 709,212 travelers used the airport.

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