U.S. airlines are grappling with soaring jet fuel costs again after the return of hostilities in the Middle East shattered the three-week-long U.S.-Iran ‘deal to make a deal’ and sent Brent crude oil prices soaring past $100 per barrel again. The U.S. jet fuel market has been tightening since March, although there haven’t been concerns about any shortages in America, unlike in Europe, which in April was supposed to run out of stockpiles within six weeks. Europe didn’t see shortages, but the global markets tightened, and…