Passenger traffic at T.F. Green Airport was down more than 9 percent last month when compared with the same month a year ago, according to the latest figures from the Rhode Island Airport Corporation.

That’s the steepest drop in nine straight months of declines at the state’s main commercial airport.

Kevin A. Dillon, president of the airport corporation, attributed the decrease to the airline industry’s reaction to increased jet fuel prices and to the general state of the economy.

“When you have a sizable part of your market as leisure travel, people are going to react in bad economic times,” Dillon said.

July traffic fell from 475,454 last year to 430,725, a decline of 9.4 percent. That followed a June that was down 8 percent from the previous year.

The only month that didn’t post a drop in total passengers in the last nine months was February, which rose 1.9 percent. But, when February’s extra day this year because of leap year is taken into account, average daily traffic fell 1.6 percent that month.

October last year is the last time a month saw an increase in average daily traffic when compared with the same month a year earlier.

Dillon predicted the airport could see a similar turnaround this October.

That’s because some airlines that serve Rhode Island plan to increase their seating capacity then by switching to larger planes. “They’re finding a way to deliver more seats in the Providence market,” Dillon said.

Dillon said US Airways plans to add seats in its New York market and United in its Chicago market in October. That will affect not only flights bound to and from those destinations but those that make connections in those cities, including those starting or ending in Rhode Island.

Dillon said the airlines are still trying to match the right number of seats to the right airports as they seek to stay profitable while crude oil and jet fuel prices remain high. Airlines used to be happy with 70 percent of the seats filled on any given flight. Now, he said, they look for a percentage in the 90s.

The problem is not that Rhode Islanders have given up flying or that others no longer want to visit the Ocean State. The question is how much they’re willing to pay. “There’s still very strong demand in this market, but it’s demand for that $79 ticket to Florida,” he said.

As the cost of flying has gone up, people’s disposable income has been eaten up by the soft economy and rising prices on everything from food to electricity. “As the economy goes, so goes this industry,” Dillon said. “What’s occurring here at T.F. Green is not unlike what’s occurring at every other airport across the country.”

The national Air Transport Association has predicted a 5.7-percent drop in people flying during the eight-day holiday travel period around Labor Day this year when compared with last.

“I suspect we’ll be somewhere near that national average,” said Dillon. “Typically September is one of the lowest months in terms of travel.”

That usually changes a bit in October, he said, as people head to New England for fall foliage.

Southwest Airlines remains Green’s biggest carrier, with more than half the 2.8 million passengers who have traveled through the airport so far this year. US Airways is in second place, with about 20 percent.

So far this year, Southwest has brought 105,603 more passengers through Green than it did last year. That, however, has been offset by decreases at other major airlines, including 74,653 by United Airlines, 19,919 by Delta and 20,304 by US Airways.

T.F. Green traffic

Most airlines have shown a drop in business so far this year

SOURCE: Rhode Island Airport Corporation

NOTE: Figures for commuter airline subsidiaries are included in the totals for major airlines.

pparker@projo.com