Overall airline passenger satisfaction has dipped slightly, according to the J.D. Power and Associates 2012 North America Airline Satisfaction Study, released Wednesday. The change wasn't dramatic -- the overall score for the year is 681, down from 683 last year, on a 1,000-point scale. But it follows two years of consecutive increases, and it's attributable to customer dissatisfaction with traditional carriers, which dropped four points to 647. Low-cost carriers fared much better, increasing three points to 754. "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," noted Stuart Greif, vice president and general manager of the global travel and hospitality practice at J.D. Power and Associates, in a statement. Customer satisfaction is measured on performance in seven categories, which are, in order of importance: cost and fees, inflight services, boarding/deplaning/baggage, flight crew, aircraft, check-in and reservations. Checked baggage fees were a customer sore point; the two airlines with the highest customer satisfaction scores, JetBlue Airways and Southwest Airlines, do not charge fees to check the first bag. Overall, JetBlue took top honors in the low-cost carrier category for the seventh consecutive year, and Alaska Airlines ranked highest among traditional carriers for the fifth straight year. Comparison charts may be found here.