Сначала понял, что он получает мили каким-то образом за сами полёты, но в другой более подробной статье уже описано что-то весьма смахивающее на наши штучки-дрючки:

One of the fundamental steps a Hobbyist can take is choosing an airline to compete for top-tier loyalty status; Schlappig chose United. Nothing was free up front — the object of the game was a return on investment. A Hobbyist doesn’t spend unless he can get the same or greater value in return. It took Schlappig about a year to master the dozens of convoluted techniques, exploiting mistakes in ticketing algorithms and learning the ins and outs of the frequent-flyer programs airlines had created after deregulation in the late 1970s. The second leg of the game is credit cards — collecting and canceling as many as possible, and deploying a series of tricks to reap the reward points that bank-and-airline-card partnerships would virtually give away. As he delved deeper, Schlappig learned about a third level, a closely guarded practice called Manufacture Spend, where Hobbyists harness the power of the multitudes of credit cards in their pockets. Airline-affiliated credit cards award points for every dollar spent, so over the decades, Hobbyists manipulated the system by putting purchases on credit cards without ultimately spending anything at all. At its simplest, this included purchasing dollar coins from the U.S. Mint with a credit card and immediately using them to pay off the charge. Schlappig read one detailed post after another that insisted Manufacture Spend was the only true way to fly for free — like sliding a coin into a slot machine and yanking it back with clear string.

Eventually, the best way he learned to visualize this bureaucratic gamesmanship was to see it as a series of table games on a sprawling casino floor — and if the airlines were the house, Schlappig realized, the Hobbyists were the card-counters.