enlarge Gordon Chibroski/Staff Photographer

Passengers go through security checks as they head for boarding areas at the Portland jetport. August was the 16th straight record-breaking month for total passengers there.

The numbers of available flights and passenger seats at the Portland International Jetport are expanding this year, even as they shrink at airports elsewhere in the country.

Capacity at Portland is projected to be up 15 percent in November from the year before, according to a report by Joel Antolini, a consultant with Seabury Airline Planning Group. Nationally, airport capacity is expected to be down 9 percent for the same period, as airlines trim their routes in the face of a weak economy and high fuel prices. Capacity is also eroding at the airports in Boston and Manchester, N.H.

At the Portland jetport in August, monthly passenger traffic topped 200,000 for the first time. There were 203,580 passengers, up 8.7 percent from a year earlier. It was the 16th straight record-breaking month for the jetport.

"Hopefully, we're going to continue to 17, 18, 19, 20 – forever – with the increases, month over month, year over year. That's my goal," said Gregory Hughes, the airport's marketing manager.

Much of the growth in Portland stems from the low-cost carriers, which account for 28 percent of passenger seats. JetBlue arrived in Portland in May 2006 and AirTran Airways in June 2007.

"They've grabbed that without robbing from the legacy carriers. They've expanded the total pie" for Portland, said Paul Bradbury, the airport manager.

The low-cost carriers are credited with a decrease in the average fare for Portland. The average price is down 14 percent since their arrival, according to Antolini's report.

Bradbury is enjoying the growth, but he does see a plateau. There are 3 million annual passenger trips in Portland's market area, and it served 1.7 million in the fiscal year ending in June, he said.

Bradbury expects the growth to level off when Portland serves between 2 million and 2.2 million, which is projected to take place in 2013.

Plans for a terminal expansion are moving forward. Those plans do not hinge on the growth projections for 2013, but are designed to meet current capacity, Bradbury said. The last expansion was in 1995, when the airport served 1.6 million passengers.

Meanwhile, other airports are not having the same success as the jetport. The Manchester-Boston Regional Airport lost three Baltimore flights last month when Southwest Airlines, another low-cost carrier, eliminated almost 200 flights.

The Manchester airport had already seen a decrease in passenger activity. In July, passenger volume was down 6 percent from the year before after a period of steady single-digit growth, said Tom Malafronte, the assistant director for air service development and marketing.

A transition has taken place in recent years with the arrival of additional low-cost carriers in the region, Malafronte said.

"We've probably lost some to the Portland area, as a result of them having two low-cost carriers," he said.

This month, AirTran made some seasonal changes in Portland, such as suspending an Orlando, Fla., flight and going from four to three daily Baltimore flights, said Cynthia Tinsley-Douglas, an AirTran spokeswoman.

"When it's seasonal, it does come back," she said.

US Airways will be adding flights next month. There will be two daily flights most days to Charlotte, N.C., up from one daily flight; five flights to Washington, D.C., instead of four; and five flights to New York City instead of four. The total number of flights to Philadelphia in a week may be down one, but most days will still have five flights.

"We like to make sure we're putting flights where there is demand," said Valerie Wunder, an airlines spokeswoman.

Staff Writer Ann S. Kim can be contacted at 791-6383 or at:

akim@pressherald.com