Mr. DeHaan said he did not expect any immediate action by the airlines.
“There’s a lot of pressure on fares right now, and it’s going to be a challenge raising fares, especially in the summer,” he said. If current jet fuel prices emerge as a new norm, he added, “I would look for more increase in the fall.”
And eventually, the high price of fuel could put newly added routes on the chopping block, said Patrick Surry, chief data scientist at the travel app Hopper. “If it continues to rise, we’ll start to see a knock-on effect on pricing and consolidation, maybe some shrinkage of capacity and routes,” he predicted.
George Hobica, founder of Airfarewatchdog, said investors’ concerns would add a sense of urgency to how and when airlines responded.
“Wall Street is just going to slam them if they don’t increase prices or reduce capacity,” he said.
This might not mean higher base fares, thanks to greater competition from low-fare carriers, Mr. Hobica said, but travelers might see fuel surcharges become common again, or have to pay higher fees for checked bags, Wi-Fi and other ancillary services.
In particular, industry experts predicted that travelers flying internationally, booking business-class and premium-economy seats, and flying less competitive routes — especially to or from smaller airports — could expect to pay more in the fall. They may also have fewer flights from which to choose.
“This summer may well be the last time you’re going to get a great price to Europe,” Mr. Surry said.