I’ve been hearing commercials for discount round-trip airfares that have a peculiar requirement: you have to spend a Saturday night at your destination before returning home. In other words, if you leave Tuesday and come back the next day, you pay full fare, but if you leave Tuesday and come back eight days later, you save big dough. This makes no sense. Why do the airlines care where you spend your Saturday nights? Do they get kickbacks from the owners of foreign fleshpots? Rip the lid off this one, Cecil, I smell a rat. –Listener, Mike McConnell show, WLW radio, Cincinnati, Ohio

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Airline moguls are devious, tovarich, but they’re not that devious. Deep discount air fares, the ones that usually involve a Saturday requirement, are aimed at pleasure travelers who otherwise couldn’t afford to fly. They’re explicitly not aimed at business travelers, who constitute about half of all passenger traffic. Business travelers pay full fare now without complaint, they’re not going to fly appreciably more if the fares are lower, and the airlines figure there’s no sense sabotaging the profit margin.

Speaking of airfare anomalies, ever wonder why flying from Saint Louis to Chicago one way costs $59, while flying from Saint Louis to Indianapolis (a shorter distance) costs $200? It’s because TWA, the dominant carrier out of Saint Louis, has competition on the route to Chicago, but none on the route to Indianapolis. Similar situations occur in many markets nationwide, thanks to the Reagan administration’s permissive attitude toward airline mergers. For more on the whole sad story, read the June 1988 issue of Consumer Reports.

Cecil’s latest book, More of the Straight Dope (Ballantine, $8.95), is now available at bookstores.