And yet otherwise environmentally conscious consumers continue to do it. Jared Bierbach, an environmental protection specialist for the U.S. Department of Energy in Washington, D.C., said he was concerned about the impact of travel. He does not own a car and said he and his colleagues work hard to reduce unnecessary work trips. But as an enthusiastic traveler in his personal life, he made a status run to Barcelona for the weekend last December rather than give up platinum status on American Airlines for 2020. “It was about exactly the right amount of miles,” he said. “To me it was very worth it. I’ve gotten upgraded a lot and value being able to board first.”

As for the environmental cost of his status run? “It did not cross my mind at all,” he said. “That’s probably something I’ll think about now.”

In December, Albert Hsieh made two cross-country round-trip flights to maintain his status on Alaska Airlines: a weekend flight from San Francisco to New York to visit friends and a quick trip from San Francisco to Boston. Really quick: He had a lobster roll at Stephanie’s, an airport restaurant he’d been wanting to try, and flew back in the same airplane. Mr. Hsieh, 33, writes the JetAlbert blog and advises private clients on how best to collect and use points. “I’m deeply interested in flying, so it didn’t feel out of the norm,” he said. “It was more enjoyable than less.” And, like so many other frequent fliers, it’s part of his job to travel.

He hadn’t really considered whether it was a waste of jet fuel. “Yeah, that’s a great point,” he said. But he added that he felt comfortable flying with Alaska, a carrier he admired for being vocal about sustainability, and that he believes it is the role of the government and industry, not of consumers, to push toward carbon neutrality.

The mileage run is dying

Mileage runs are now on the decline as airlines move toward rewarding customers based on the amount they spend rather than the number of miles they fly. Carriers may make money from mileage-run flights, but many see them as a hack for those who don’t fly enough — or spend enough — to merit higher status.

“I wouldn’t say the mileage run is completely dead, but it’s on life support,” said Scott Mayerowitz, executive editorial director of The Points Guy, a travel site that gained prominence as a go-to publication of frequent fliers and award cravers. “The traditional mileage run was that you found a really cheap $200 to $300 ticket to Europe and you were rewarded on distance and nothing else. Those days are gone.”