Jet fuel prices have more than doubled since the start of the Iran war in late February, costing airlines billions of dollars and leading to a rise in global airfare . Now, a major shortage of aviation fuel is looming in Europe, with the head of the International Energy Agency saying the region has about six weeks of jet fuel left, the Associated Press reports. In order to help mitigate costs, some airlines have paired back their schedules or suspended specific routes, leading to a small spike in flight cancellations. However, airlines have not yet had to cancel flights due to the shortage of jet fuel itself. “The good news is that the marquee destinations of the world aren't losing airline service, or even many flights,” says Mike Arnot, an airline industry consultant. In the US, carriers are largely focusing cuts on flight routes that traditionally see lower demand, like red eyes or those that take off in the middle of the week.…