The casinos, of course, hope that a player will stay loyal to the brand and only play at their properties. But because locals are bound to have access year-round, many of them will carry a variety of cards and use the one they need when they happen to be in that casino.

Casino programs offer comped rooms, free meals, line passes and bonus play based on the amount of money wagered.

But loyalty programs work a little differently for airlines.

Experts say a frequent traveler is best served signing up for the loyalty program with the airline used most often. And, in Las Vegas, that usually means signing on with one of the five largest carriers serving McCarran International Airport -- Southwest, America West, United, Delta or American.

But members of Southwest Airlines' Rapid Rewards program recently expressed some disappointment in seeing their program devalued.

Southwest has a frequent-flier program that is unique to the industry. Awards are calculated based on the number of one-way flights flown, not the number of miles traveled as on other airlines. On Southwest, if you fly 16 one-way trips within a year, you get a free round-trip ticket anywhere on the Southwest system.

That means, for example, that if you fly frequently to Reno and take eight round trips, you get a freebie and you can use that go as far as Manchester, N.H., or West Palm Beach, Fla.

For years, Southwest has attempted to create incentives for travelers to buy their tickets directly from southwest.com, the airline's Internet site.

Instead of giving one credit for a one-way trip, the airline offered two. That meant you could get a free ticket after four round trips.

Several months ago, Southwest cut its two-for-one bonus back and offered 1 1/2 credits per one-way trip. There was some mild grumbling about the cutback and Southwest set a deadline for the end of that program -- June 30, 2004. That was extended to Dec. 31, 2004. Then, to April 1, 2005. And that's when it ended. As of last month, Rapid Rewards members got no bonus credits for booking online.

"The program has done its job and we kept with the expiration date," said Southwest spokeswoman Whitney Eichinger.

She said that today, nearly 63 percent of the airline's bookings are from customers who purchase online.

Eichinger said the airline has not seen a decline in bookings since the bonus feature expired, partially because the airline has opened a new market in Pittsburgh and the response there has been great.

So should customers abandon Rapid Rewards for a program that is more rewarding?

Southwest's credit system is still quite appealing to most customers and Southwest customers are fiercely loyal.

"The short haul means as much as the long haul, creditwise," Eichinger said. "And the other thing people like about it is that the award is sent directly to you when you earn it. You don't have to request it or keep a tally in your head. It automatically arrives at your house."

Southwest's top competitors in the Las Vegas market have their own loyalty programs that have their own advantages. America West's FlightFund program offers free travel after 15,000 miles of flying -- but that's only for a short-haul flight. Free trips on long-haul routes require 25,000 miles of flying.

United Airlines, the No. 3 McCarran operator, has a program called Mileage Plus in which awards are made after 25,000 miles of flying.

Both America West and United also offer the options of burning miles to upgrade a ticket from the coach section to first class (Southwest offers only one class of service) and miles can be earned and awards can be used on other partner airlines, so they could be used internationally.

All three airlines offer miles or credits for using partner companies at hotels and for car rentals and all have branded credit cards that help travelers accumulate awards faster.

Eichinger said Southwest will likely continue to run certain promotions to offer certain travel incentives in the future. For example, Southwest for 10 weeks last year offered bonus credits if a Visa credit card was used for an online purchase. Visa is a Southwest partner company.

There are a number of resources available on the Internet to help travelers choose a frequent-flier program. Frequent Flyer magazine, InsideFlyer and webflyer.com offer tips, reviews, ratings and forums for club members to talk to each other about industry trends.

Not surprisingly, United fliers are nervous about the fallout that could occur with the U.S. Bankruptcy Court decision earlier this week to approve the airline's termination of its pension plan. Four unions have threatened strikes of the airline in response, but participants in a United forum on webflyer.com indicate they will continue to book on the airline.

InsideFlyer magazine recently handed out its "Freddie Awards" to airline frequent-flier programs and Southwest and America West fared well in the awards, which are determined by frequent fliers submitting ballots.

America West's FlightFund won in the 2004 Best Award category (Southwest won the award in 2003). Southwest won the Best Bonus award and has won it every year since 1998.

The Best Customer Service Freddie went to Southwest, which has won the category every year since 2001, and it also won the Best Award Redemption for the seventh year in a row.

The Best Elite Level Award went to America West, which has won in that category every year since 2002.

When it comes to frequent-flier programs, Las Vegans have some good options.

Richard N. Velotta covers tourism for In Business Las Vegas and its sister publication, the Las Vegas Sun. He can be reached at (702) 259-4061 or by e-mail at velotta@lasvegassun.com.