STRAIT OF HORMUZ — Chevron Chief Executive Officer Mike Wirth said the standoff with Iran over the Strait of Hormuz is pushing fuel prices higher and tightening jet fuel supplies, with aviation likely to feel the impact most quickly. He said travelers could see fewer flights, fuller planes and higher fares in the coming weeks.

"We've seen some upward pressure on gasoline prices now. I think aviation is clearly an area where it's going to probably get worse over the next few weeks," Wirth said.

He described a rapidly tightening market for jet fuel outside the United States. "We are seeing jet fuel tighten very quickly in Europe, in Asia, and we're seeing airlines announce adjustments in their flight schedules. We're seeing it flow through into fares. I think that's one of the first places it will be felt most broadly," he said.

Wirth said a jet fuel shortage already existed in certain parts of the world before the war with Iran began on Feb. 28. Since the start of the conflict, airlines have raised bag check fees and cut routes. U.S.-based carriers are slightly better positioned than European airlines because the U.S. produces its own jet fuel.

He added that market conditions would reshape airline schedules, saying the upward pressure on prices and tightness in the market is likely to lead to further route optimization, that flights may not be as abundant as they otherwise would have been, and that planes will probably be more full than they would have been. "And yes, fares — fares could be higher," he said.

Jet fuel prices in North America have climbed more than 80% compared with this time last year, according to the International Air Transport Association. At the pump, the average cost of gasoline nationwide was $4.03 per gallon on Thursday, nearly a dollar more than the price per gallon a year ago. Diesel stood at $5.47 per gallon on Thursday and has risen more quickly than regular gasoline.