Major U.S. airlines are voicing concerns over a significant increase in jet fuel prices, which is expected to contribute to elevated costs during the busy summer travel season. According to Airlines for America, jet fuel prices in Chicago, Houston, Los Angeles, and New York averaged $3.18 per gallon on Tuesday, registering a more than 30% surge compared to July 5. As fuel and labor costs represent the largest expenses for airlines, the spike raises questions about the extent to which carriers have been able to pass the increased costs onto customers this summer, following a decline in fares from last year.