Turbulence Ahead

Charleroi, a grimy, working-class town in southwest Belgium, was big in the Industrial Revolution. Its mines once churned out 10 million tons of coal a year. All that's left of that heyday are 62 slag heaps. Even covered in grass, they're not what you'd call a tourist attraction. Yet approximately 2 million people a year come to this forgettable place — thanks to a revolution in Europe's airline industry. In 2000, Irish discount flyer Ryanair agreed to make an international hub of Charleroi's airport, when the town shaved standard landing charges from €7 to €1 per passenger and provided money for...