The airline sector is trading sharply lower as the expiration of a U.S.-Iran ceasefire agreement raises geopolitical tensions in the Strait of Hormuz, a critical channel for global oil supply. Traffic in the strait has reportedly dropped significantly, creating substantial risk of a spike in crude oil prices. Since jet fuel is a primary operating expense for airlines, the prospect of higher fuel costs is pressuring the sector's profitability outlook, leading to a broad sell-off in airline stocks.