JetBlue Airways’ frequent-flier program is the tops when it comes to customer satisfaction.

That’s according to J.D. Power, which rolled out its 2017 Airline Loyalty Program Satisfaction Study on Wednesday. While J.D. Power has rated airline customer satisfaction for years, the latest study is the group’s first to look specifically at airline loyalty programs.

“As loyalty programs have exploded in popularity over the past several years, airline loyalty program managers understand the critical role that ancillary benefits that fall outside the airline industry can play and they devote careful attention to partners included in their programs,” Michael Taylor, Travel Practice Lead at J.D. Power, said in a statement.

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The 2017 study of loyalty programs found that overall customer satisfaction with a program increased significantly when customers could earn or redeem miles and points not only on flights, but also for tertiary items like restaurant meals out or renting cars.

“Flexibility in how miles are redeemed is valued by members,” Taylor added. “After all, if you win a pie-eating contest, you may want to be rewarded with something besides another pie.”

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Perhaps unsurprisingly, other perks – such as “waiving a same-day change fee” or awarding a top-tier frequent-flier status – dramatically impacted a user’s satisfaction of the program.

As for the individual airline ratings, J.D. Power tabbed JetBlue’s “TrueBlue” as the best of six U.S. loyalty programs it looked at.

JetBlue’s program earned a score of 800 on a 1,000-point scale, narrowly edging out second-place finisher Alaska Airlines Mileage Plan (796) and Southwest Airlines Rapid Rewards (793).

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J.D. Power said its study measured member satisfaction with the loyalty programs based on four factors. In the order of importance, they were: earning and redeeming rewards; program benefits; account management; and member communication.

Delta Air Lines placed highest among the so-called legacy airlines, finishing fourth overall with a score of 766. That narrowly bested the industry average score of 760.

Rounding out the rankings were American Airlines AAdvantage (fifth place, 729 points) and United Airlines MileagePlus (sixth place, 727 points).

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