Travelers may love the idea of airline loyalty programs, but they don't love the complex reward structures and many hoops to jump through. For the third year in a row, this has led to a significant negative effect on overall consumer satisfaction regarding airline rewards programs, according to the J.D. Power 2019 Airline Loyalty Program Satisfaction Study.

The study shows that member satisfaction climbs when members understand how to earn and redeem points, yet nearly half (45%) of loyalty program members say they do not completely understand how to redeem rewards and 43 percent say they do not fully understand how to earn miles or points.

"This is the third year in a row that we've seen airline loyalty program customer satisfaction hampered by a widespread lack of understanding of how to extract the most value from the programs," says Michael Taylor, Travel Intelligence Lead at J.D. Power.

In addition, programs have turned away from their frequent-flyer roots. "Many airlines are evaluating the success of their loyalty programs based on dollars spent rather than on miles flown," says Taylor. "That's a significant shift away from rewarding frequent travelers and toward rewarding high spenders."

The J.D. Power Airline Loyalty Program Satisfaction Study measures overall satisfaction among passengers who are enrolled in an airline loyalty program. Satisfaction is measured across four factors: member communication; earning and redeeming points; program benefits; and account activities.

The study revealed some clear correlations between brand engagement and satisfaction with a loyalty program. For example, satisfaction jumps when airline staff members recognize a member's status during the booking, check-in, departure or flight.

Want an easy way get more out of your airline's loyalty program? Download the app. Members of loyalty programs who also use the airline's mobile app are significantly more satisfied than members who don't use the app, according to the study. Just over half (56%) of program members report that they have downloaded the app on their smartphone or tablet.

For the third year in a row, JetBlue Airways TrueBlue ranks highest in overall member satisfaction, beating the industry average by 33 points with a score of 821. Southwest Airlines Rapid Rewards (812) ranks second and Alaska Airlines Mileage Plan (810) ranks third.

The major legacy carriers did not fare well in the study. While Delta Airlines SkyMiles (791) edged out the industry average (789) to take fourth place, the industry's other two legacy carriers pulled up in the rear.

Here are the top airline loyalty programs, according to the study:

- JetBlue Airways TrueBlue

- Southwest Airlines Rapid Rewards

- Alaska Airlines Mileage Plan

- Delta Air Lines SkyMiles

- (tie) American Airlines AAdvantage

- (tie) United Airlines MileagePlus