How can airlines curb bad behavior? Start by providing better service.

At the Toronto Blue Jays spring training home of Dunedin, Fla., almost nine years ago, a teenaged prospect walked into the front reception area of the team’s minor-league complex to meet a reporter. He had medium-length dreadlocks poking out from under his Jays cap, didn’t look the least bit capable of growing a beard and was a little on the chubby side. But he was already one of the most fearsome would-be sluggers in the sport. “Hello,” said Vladimir Guerrero Jr., in rehearsed English. “Nice to meet you.” The Blue Jays of spring 2017 were in a bit of an odd spot. Two years...