An hour before sunrise in August, Southwest planes are lighted inside and ready to go at T.F. Green Airport, in Warwick. The airline has announced that it is changing its scheduling to match demand.

The Providence Journal / Bob Thayer

As passenger traffic at T.F. Green Airport continues to sag, plans by Southwest Airlines to reconfigure its schedule will bring good news and bad news to Rhode Island, according to the head of the state airport agency.

“Southwest is looking to become a little bit more dynamic in terms of their schedule,” said Kevin A. Dillon, president of the Rhode Island Airport Corporation, the agency that runs Green and five smaller state airports. The airline, which accounts for about half of the passenger traffic at Green, is changing its scheduling to include seasonal flexibility, adding or cutting flights more frequently to match demand.

Dillon has said that the entire airline industry is looking for greater flexibility in the wake of meteoric rises in jet fuel prices this summer that forced many airlines to cut flights.

He said Rhode Island could benefit from Southwest’s move at times when demand for flights here is higher than at other airports Southwest serves. On the flip side, if Rhode Island has slackening demand, the airline could pull flights.

If recent history is a guide, Dillon said, Green could be positioned well. While two other New England airports served by Southwest — Bradley International in Connecticut and Manchester-Boston Regional in New Hampshire — have recently seen reductions, Green has gotten flights added.

“We continue to be the beneficiary in increased seat counts,” he said.

Much of that has to do with the airport’s demography and geography, Dillon said, adding that two-thirds of New England’s population live within 75 miles of Green.

Even so, passenger traffic through Green continues to drop sharply from a year ago.

In September, 368,416 passengers traveled through Green, compared with 415,507 in September of last year. That’s a decrease of 11.3 percent and marks the 11th straight month of declines, when factoring in the extra day in February this year. But last month, for the first time since April, the size of the decrease got smaller when compared with the previous month. The percentage declines over the same month in the previous year for April through August were, in order, 0.4, 3.3, 8.0, 9.4 and 11.7.

“Even though we’re down, I still feel good about the picture here in Providence compared to what’s happening in the rest of the country,” said Dillon. “I do believe we’ve kind of seen the bottoming out. As we progress toward the end of the year, beginning in October, the passenger loss will not be as severe.”

He issued one caveat with that forecast, though: “The other piece that figures into this is the economy.”

If the economy continues to erode, Dillon said that it could eat into the rebound from the summer reductions in airline seating capacity related to the escalation in fuel prices.

Among Green’s six largest airlines (including commuter airlines providing service under an associated brand name), Southwest had the third-largest percentage decline in passengers this September compared with last, at 15.7 percent. Northwest Airlines was the largest, with a 19-percent drop, followed by Delta Airlines, 18.7 percent. United Airlines fared better than Southwest, dropping 5.5 percent.

Two of the six largest saw gains: Continental Airlines, up 4.8 percent, and US Airways, up 2.0 percent.

Even though Southwest shed 32,614 passengers this September from last, the airline is still up when comparing year-to-date figures. Last year through the end of September, Southwest carried 1.84 million passengers through Green. This year, it had 1.87 million.

Green also may have turned another corner in September: It was the first month since May that its passenger losses were not the sharpest among the three “Boston” airports, including Logan International and Manchester. While final numbers were not available, officials at Manchester estimated their September loss would be 12 percent to 15 percent and, at Logan, 8 percent.

At Manchester, Southwest accounts for 56 percent of the airport’s passengers, while the airline accounts for 47 percent of the passengers at Green. Southwest does not serve Logan.

pparker@projo.com