Atlanta-based Delta Air Lines ranked third among major network airlines in the closely-watched J.D. Power and Associates airline satisfaction study, moving up a couple of notches after two years of declines.

Delta came in behind Alaska Airlines and Air Canada, and was the only airline in the category to improve. Jessica McGregor, senior manager at marketing information company J.D. Power, said Delta improved across the board, with the biggest improvements in flight crew, in-flight services and aircraft.

Overall, the major network airlines "still struggle to meet travelers' expectations," according to the study.

In the low-cost carrier segment, Southwest Airlines ranked second, while AirTran Airways came in fourth out of five carriers ranked.

Delta is the largest airline at Hartsfield-Jackson International Airport, followed by AirTran. Dallas-based Southwest, which began service to Atlanta in February, acquired AirTran and is gradually converting AirTran operations into Southwest.

The study showed overall passenger satisfaction with airlines has declined, with improvements at low-cost carriers offset by declines at the major network carriers.

"The airline industry is caught between trying to satisfy customers who demand low prices, high-quality service and comfort, and contending with the economic challenges of profitably operating an airline," J.D. Power Vice President Stuart Greif said in a written statement. "Passengers want it all, but they are not necessarily willing to pay for it all."

The study, based on responses from more than 13,500 passengers flying between May 2011 and April 2012, measures customer satisfaction based on cost and fees, in-flight services, boarding/deplaning/baggage, flight crew, aircraft, check-in and reservation. Checked baggage fees are a "customer sore point," according to the study.

Delta Chief Executive Richard Anderson watches the study results, even including them in the company's annual goals. Under the category with the tagline "Build a better airline," the first goal listed is to earn the J.D. Power award among network carriers.