(CNN) -- Airline satisfaction might seem like an oxymoron these days, with fees and cramped cabins making flying miserable for many people, but fliers are giving the industry better marks, a new survey finds.

Passenger satisfaction with carriers has improved for the second year in a row, according to the J.D. Power and Associates 2011 North America Airline Satisfaction Study released Wednesday.

Low-cost carriers scored particularly well, reaching a five-year high in customer satisfaction.

Also getting high marks: The check-in and reservation process for all airlines.

Despite initially balking at the automation of those tasks, passengers "now appear more satisfied with the convenience and speed that technology has enabled," said Stuart Greif, a vice president at J.D. Power and Associates.

The one area where passengers aren't expressing more contentment is cost and fees. Satisfaction with base fares has declined across every airline, the study found.

As the economy improves and more travelers return to the skies, many airlines have raised fares from the lower rates charged during the recession, J.D. Power and Associates said.

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The dreaded fees for food, drinks, checked bags, priority boarding and seat upgrades also continue to weigh on air traveler satisfaction.

So how did individual airlines do in the survey?

Alaska Airlines ranked highest in overall satisfaction among traditional carriers for the fourth year in a row, followed by Air Canada and Continental.

US Airways was at the bottom of the list.

Among low-cost carriers, JetBlue Airways received the highest overall satisfaction scores for the sixth year in a row, followed by Southwest and WestJet.

Frontier Airlines was ranked the lowest.

The study was based on responses from more than 13,500 passengers who flew on a major North American airline between July 2010 and April 2011.

They were asked to grade carriers in seven categories: cost and fees, in-flight services, flight crew, aircraft, boarding/deplaning/baggage, check-in and reservation.