Given all the pain points that make up plane travel — from delayed flights to cramped seats to what seems like an endless parade of new fees — it may be hard to believe that there are still customers passionate enough about an airline to want to eat off plates bearing its logo, or display its memorabilia around their homes.

At December’s sale, Mark Caldwell was one of the earliest to arrive. Mr. Caldwell, a retired entrepreneur, flies so often on Delta that he has achieved two-million-miler status, a level of loyalty that confers special benefits and recognition, like free upgrades and the occasional shout-out over the flight intercom. Even when he’s not flying, he can sit in first-class seats he bought at an earlier sale that now live in his barn.

“Chances are I sat in them when they were on the plane,” he said.