What prompts a U.S. airline to open a new route? A panel discussion yesterday at the World Routes Development Forum shed light on the question at an interesting time when airline mergers, high oil prices and other factors are making it difficult for some smaller airports to retain service and attract new service.

Scott Laurence, the senior vice president of airline planning at JetBlue Airways, told World Routes conference attendees that data accounts for about 75% of JetBlue’s decision.

But apparently that’s changing across the industry.

“The onus has shifted to the airports and their communities to put forward a compelling case to help reduce the risk for the carrier to open a non-stop flight that might cost as much as $100 million a year to operate,” the article says.

The piece reminded me of my recent conversation with Greg Kelly, the airport director of Savannah/Hilton Head International Airport, which had been facing a 20% reduction in service last year until it took action.

“Our air service issue was a big problem because of the reduced number of seats and higher fares,” Kelly told me. “So, like most airports, we set out to get more service. We knew JetBlue would fit us very well, and we worked hard to present a business case.”

The first time around, Kelly’s airport lost out to Charleston, S.C., but Charleston did so well that JetBlue “took another look at us,” he said.

For the second pitch, the tourist-reliant Savannah and Hilton Head communities beefed up the support and incentives they offered to JetBlue.

“Not just support from a marketing standpoint but from a cash standpoint,” he said. “That did the trick.

“They started on Feb. 13. That’s when our fortunes changed. We had new air service coming in with a lower fare structure,” Kelly said.

Since JetBlue started service there, Delta increased capacity to keep up with JetBlue and the average fare has dropped by about 20%, he said. The Savannah/Hilton Head airport today is handling about 20% more passengers year over year, he said.

Readers: Are you noticing your favorite airport losing service? If so, how are you changing your travel habits?