By Bill Chappell The U.S. and other nations have agreed to tap into oil reserves, but the move might not do much to bring jet fuel prices down rapidly, an expert tells NPR. It's one way violence in the Middle East can affect flights around the world. Here, an Emirates airliner prepares to land at Dubai's main airport on Sunday. AFP via Getty Images hide caption The war in Iran is rattling the aviation industry, from flight cancellations to rising costs for jet fuel. So if you're planning to travel this spring or summer, should you grab a ticket now, or wait? "You should go ahead and book," says Sean Cudahy, an aviation reporter at The Points Guy travel and personal finance website. It's generally recommended to buy international flights further in advance than domestic trips. But in the current circumstances, Cudahy says he would go ahead and book even domestic flights.…