If reality television has proven anything, it is that H.L. Mencken was onto something when he said, “No one in this world . . . has ever lost money by underestimating the intelligence of the great masses of the plain people.”

The threshold for what people find entertaining has been set fairly low, and some cynics suggest it’s a limbo bar that gets lower as mankind moves forward.

But still.

A bar near Dulles International Airport is providing its customers with headphones so that they can listen in as air-traffic controllers talk to airplane pilots.

Controllers provide a vital service, but most of them would probably trade their seats in front of a radar screen for jobs as professional comedians if they had that talent. Even the funny ones, however, take their job too seriously to engage in a lot of entertaining banter with the cockpit crew members with whom they do business.

Sure, there are times when traffic gets slow that might allow for chitchat, but Dulles handles more than 300,000 flights a year, and commercial flights tend to flock like starlings to take off and land at the hours most convenient to their passengers.

But the experiment is on at O’Malley’s Pub, in the airport’s Holiday Inn. The bar and restaurant is providing patrons with wireless headphones so they can listen in as they look out the window at planes taking off and landing.

“It’s more for kids, because they can look out the window and see the planes coming and going,” said Dawn Forman, who works at O’Malley’s.

Adults pick up the headphones “occasionally,” Forman said. “It’s more out of curiosity. Once you’ve flown in a plane, you’ve flown in a plane.”