Iranian commercial airlines face a near-total international shutdown beginning September 23, 2026, as U.S. secondary sanctions target access to aviation services, fuel supplies, ticket sales, banking and payment processing. Treasury Secretary Scott Bessent said carriers landing abroad cannot receive fuel or airport services and that businesses selling their tickets risk exclusion from the dollar system. Oil prices initially rose as U.S.-Iran tensions intensified, but Brent crude later fell below $100 a barrel for a fifth consecutive session as diplomatic efforts revived hopes of restored Middle East energy flows. The measures follow Treasury sanctions announced September 8 against more than 27 Iranian airlines and associated entities. Turkish Airlines suspended five Iranian routes until at least March 28, 2027, and Pegasus Airlines also halted Iranian services. Saudi Arabia moved about 2.9 million barrels of crude per day through the Strait of Hormuz over six days, while satellite imagery showed supertankers with approximately 14 million barrels of capacity at its Gulf export terminals, the highest level observed since at least June. Investors are watching President Masoud Pezeshkian’s planned trip to the United Nations in New York and a possible meeting with President Donald Trump.