In February, a friend told me he couldn’t meet for dinner in Washington because he was flying to Amsterdam for the weekend. Emphasis on the word “flying.” His itinerary had him spending most of the weekend traveling, but he’d stay in Amsterdam for only 14 hours, after connecting through Paris and Istanbul to get there; his return trip involved a layover in Minneapolis.

It’s a practice known as a mileage run: Buy a low-price airline ticket, in this instance $537, and fly not because you want to go anywhere, but to earn redeemable miles and progress toward elite status on your preferred airline. The core logic behind mileage runs is that airline points have a relatively fixed value, but the cost to accrue them can vary widely, so a low fare for a long trip can reap outsize rewards. Only when you’re taking a mileage run is connecting through Istanbul to get to Amsterdam better than flying there nonstop.

Mileage running arguably makes sense for some travelers, that is, the sort of people who don’t mind spending a weekend on airplanes going nowhere in particular. These people have a well-established subculture; the Mileage Run forum on FlyerTalk, an online travel discussion board, has generated more than 24,000 threads. But mileage running has never made much economic sense for the airlines. The purpose of a frequent flier program is to build loyalty and retain customers who generate a lot of profits. Mileage runners aim to buy tickets with the lowest cost per mile and extract as many points as possible from them; this is not high-margin behavior the airlines should want to encourage.

And increasingly, they aren’t.

In the last year, United Airlines and Delta Air Lines have made two major changes to their reward programs that make mileage running a lot less useful. First, they imposed a minimum spending requirement to obtain elite status. Previously, you became a “silver” or “gold” or “diamond” flier by traveling a minimum number of miles or segments in a year. Now, to qualify you must also spend a minimum amount on airfare; for example the status tier for traveling 25,000 miles also requires $2,500 in airfare spent, or 10 cents per mile. (The Amsterdam-Istanbul itinerary I described above cost just 4.6 cents per mile.)