With 50 million members, the success of frequent-flyer programs has influenced marketing in every industry. In travel and leisure alone, frequency programs are becoming tools of the trade - and both consumers and businesses are discovering first-class rewards. Since American Airlines unveiled the first mileage-based, frequent-flyer program in 1981, plastic-card frequency programs have been spreading throughout the travel and leisure industry. Car rental companies offer frequency programs, where mileage is redeemed for free upgrades or rentals. Hotels have frequent-stayer clubs, where guests get special VIP treatment. Hotels also recognize the security and branding value of re-programmable plastic cards for room access. They're fast replacing clunky, nondescript room keys - and are often requested as keepsakes by their guests. Leading resorts are also turning plastic cards into free play time for corporate incentive programs. What better way to present travel rewards to employees than distinctive plastic cards that entitle them to the perfect weekend or week-long getaway? Casinos are also adding plastic cards to their marketing treasure chests. Cards issued to each guest are swiped through card readers at gaming tables. Guests accumulate points and redeem them for prizes and services. In turn, the casinos can track playing time, gaming preferences, and other data for one-on-one marketing.