United Airlines, American Airlines and Southwest Airlines are cutting or reconsidering marginal flights as oil prices exceed $100 a barrel and jet fuel reaches $4.53 a gallon as of Thursday. Airline executives said strong demand has not offset the fuel shock and that capacity reductions and higher fares could follow if elevated costs persist, although fuel-cost pass-through typically takes time. U.S. airfares rose more than 23% year over year in August, while checked-bag and seat-selection fees have also increased. Earlier reporting cited jet fuel at $4.71 a gallon, American’s projected $1 billion increase in fourth-quarter expenses, Southwest halving its planned capacity growth, and Ryanair reducing its passenger forecast to 214 million from 216 million. Travelers also face the loss of Spirit Airlines’ low fares after its May shutdown, with analysts advising early bookings and refundable tickets where possible.