Accelerated refinery closures in the past decade and increased dependence on kerosene from the Middle East have exposed Europe’s energy supply vulnerability once again. For years, European consumers have had to contend with last-minute strikes of ground personnel and cabin crew during peak summer travel. This year, strikes may be viewed as a minor nuisance compared to what’s coming within weeks—a jet fuel supply crisis that could ground flights and hike fares. The war in Iran has cut most of Europe’s imports of jet fuel,…