“This fee increase really is more than just going up about $3 on a ticket,” he told me in a telephone interview.

“It’s each way on a nonstop flight, and can be added again because of the layover stipulation. For a family, remember, too, that you’d have to multiply all this by four or five. So, it could price some people out of flying.”

Kaplan said if airline ticket sales start to sag after the hike, airlines could absorb some of the fee. But that would be an unusual reaction from an industry that’s been obsessed for the past few years with squeezing every dime it can from travelers.

Indeed, fees for everything from bags to a few inches of extra legroom are rampant this summer, and more could be on the way, Kaplan said.

“You could see airlines trying things like adjustable fees,” he said. “One example is that they could charge you more to handle your bags the farther you fly.”

In recent years, the industry also has seemed more inclined to reduce capacity than cut fares. Parking airplanes saves labor, maintenance and, especially, jet fuel.

And, it makes those expensive tickets a hotter commodity.