"The final jet-booster of this trend is the airlines' extraordinarily
successful frequent-flier programs, which have provided the burgeoning
hyperflier culture with its own currency, lexicon, and class structure. ...
The hyperfliers may think they're getting something for nothing, but they're
actually playing the airlines' game. By tightly restricting free flights,
airlines have rigged it so that a passenger flying for free almost never
displaces a paying customer, and typically costs the airline only about $20
per flight. But to earn that $20 flight, hyperfliers will go out of their
way to book all their tickets on one airline, and may waste hundreds or
thousands of dollars building their status."
--Warren Berger, "Life Sucks and Then You Fly," Wired, August, 1999