I think the bottom line for the airlines is... the bottom line. They would not allow a concept as large as frequent flier programs to continue if they didn't see some profit out of it. But additionally, I think most fliers do not take full advantage of the programs, and therefore, they lose out to some degree.

Of course, I don't include myself in that category. Before I reached Premiere status with United, I never flew in Business or First. Once I did hit Premiere 6 years ago, I was able to upgrade on about half of my flights, usually at no cost to me. Did I have to buy more airline tickets for the status? Nope, I simply concentrated my business and personal flying on United and soon made Premiere Executive for 2 years. Then the miles really started to pile up. The only time I recall taking an extra flight was at the end of one year when I flew from LAX to San Diego for Christmas (instead of the 2-1/2 drive) just to make sure I requalified for Premiere Executive. The cost: about $75 as I recall. I don't need to explain the benefits accrued the following year for that relatively small fee.

On the other hand, my family looks at the free trips and upgrades I earn (some of which have been shared with them) and takes a superficial approach to duplicating my success. It doesn't work, and they don't quite understand why. First, they don't fly often, so qualifying for an elevated status is almost out of the question. But even when they do fly, they take a scattered approach to bolstering their miles.

So, my parents and siblings each fly once or twice a year, but all have at least two FF accounts. The whole family went to Paris last month, and bought 6 tickets on United, despite the fact that not one of them had a Mileage Plus account (though they all signed up for one). The reason: United had the lowest fare. This is a good reason to be selective, but American (where they already had accounts) had a fare that was only about $50 a ticket more than United's. Plus, American had a 10,000-mile bonus for departures from LAX! I know the math, but they didn't think it through.

Fortunately, I was able to talk sense into my parents when they booked their upcoming San Diego-Boston trip. Least expensive fares were averaging $650 -- pretty high for coast-to-coast -- and they were all set to purchase the tickets so they could earn the miles. I had to remind them that they had 6000 American miles expiring this year, and this was exactly the time they should cash in the 50,000 miles for two free tickets!

I think the airlines count on the fact that a majority of their members cannot or chose not to take a long view of the programs, and fail to fully maximize the benefits.