A Delta Airlines aircraft at the Phoenix Sky Harbor Airport.

Delta Airlines has cemented its status as the network U.S. carrier with the worst frequent-flier program, further devaluing its long-cheapened SkyMiles. The leadership of the program or the airline — or perhaps both — doesn’t seem to understand what the loyalty business in 2011 is about. It may be time for a new team at the top.

For more than a year, Delta failed to publish an award redemption chart for most of the world, resulting in lack of transparency about how many miles were really needed for an award ticket.

When it finally unveiled a chart this week, the mileage rates on many routes were increased significantly. Many loyal SkyMiles members felt cheated and disrespected, calling Delta’s move a “stunt” in comments posted on FlyerTalk, the largest online travel community.

If you wondered why Delta announced last week the elimination of miles’ expiration, my guess is that it tried to soften the blow of what was coming — and to claim that it cares about its customers. In reality, almost everything SkyMiles has done in recent years has been decidedly customer-unfriendly. I’m not an active SkyMiles member and have no dog in this flight, but I’ve been appalled enough to write about it.

In comparison to its two largest competitors, American and United, Delta’s upgrade and award policies are the most restrictive and inflexible. Its system-wide upgrade certificates are only valid on tickets booked in Y, B and M class, and are not transferable. American’s upgrades can be used on just about any fare and gifted to other people. United’s certificates exclude only the lowest booking classes and can also be transferred.

In 2008, Delta devalued its miles by adding a third award tier, in an attempt to mask its very poor award availability at the lowest level. A year later, it devalued its elite status when it introduced a fourth tier, Diamond, on top of Silver, Gold and Platinum. If that’s not bad enough, Delta also charges some fees that are hard to justify, such as $50 for booking an award originating outside the United States.

The main reason frequent-flier programs exist is not to make customers happy, but to make money — and most of them do. I’ve never considered that a problem. A successful business deserves all the rewards it can get. My problem has been with the way airlines have been trying to make money through their so-called loyalty businesses. For decades, they have had an utterly peculiar philosophy, which can be best described at a “screw the customer” approach, which I explain with a misguided view of what the loyalty business is about.

Fortunately, a few airline executives recently saw the light, and things are starting to change. I’ve written several times about what Graham Atkinson did when he was president of United Mileage Plus for less than two years, beginning in the fall of 2008. He understood the essence of customer loyalty and showed that what’s good for the company doesn’t necessarily have to be bad for customers. While he wasn’t able to end StarNet blocking, he actually listened to customers and reversed decisions based on their feedback.

American’s AAdvantage program also has progressive leadership that rewards top fliers appropriately and has tried to make it easier for members to use their miles. There is still a lot to be desired, but it’s on the right track.

Delta, on the other hand, has been stuck in the 20th century. It seems it’s working hard to perfect the “screw the customer” approach.

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