Airlines around the world are facing rising fuel and labor expenses, pushing ticket prices higher and adding new fees for passengers already dealing with economic uncertainty, according to Axios.

Industry concerns are intensifying over a potential jet fuel shortage in Europe and Asia, which could worsen the impact of the Iran conflict on global travel within weeks if a tentative agreement to reopen the Strait of Hormuz breaks down. Such a scenario could lead to even higher fares and possible flight cancellations as the busy summer travel season nears.

Reflecting the ongoing strain, Air Canada announced Friday that it plans to suspend service to New York’s John F. Kennedy International Airport from June 1 through Oct. 25 in an effort to reduce fuel-related expenses.

Other major carriers—including U.S. airlines such as United and Delta, along with Air France-KLM, SAS, Philippine Airlines, and Cathay Pacific—have scaled back routes and either raised ticket prices or indicated they will do so if disruptions to oil shipments through the Strait of Hormuz persist.

“It’s very hard for the airlines to make predictions in this environment, so they’re going to be conservative, and that’s why it’s likely that their prices will remain elevated for some time until things really stabilize,” said Shye Gilad, a former airline captain who now teaches at Georgetown University’s business school.

Amid the pressure, United Airlines CEO Scott Kirby has reportedly considered a controversial merger with American Airlines, while Spirit Airlines is said to be nearing liquidation after filing for its second bankruptcy in less than a year in November, Axios reported.

At the same time, Southwest and other carriers are trimming less-profitable routes, and Delta Air Lines CEO Ed Bastian said Tuesday the company will need to “find ways” to pass increased jet fuel costs on to customers.

Oil markets showed some relief Friday after Iran’s foreign minister indicated that tankers and other commercial vessels could once again travel freely through the Strait of Hormuz, a critical passageway that carries roughly 20% of the world’s oil and natural gas.

Jet fuel, a refined petroleum product, represents the largest expense for airlines, accounting for about 30% of total operating costs, according to the International Air Transport Association.

Prices for jet fuel have roughly doubled since the conflict began, and industry analysts warn that supply shortages may soon follow.

In recent weeks, major U.S. carriers—including Delta, United, American Airlines, Southwest Airlines, and JetBlue—have raised fees for checked baggage.

Meanwhile, Hong Kong-based Cathay Pacific recently increased fuel surcharges by approximately 34% across its network, and Air India added as much as $280 in extra fees on certain routes earlier this month.

Other global carriers, including Emirates, Lufthansa, and KLM, have also adjusted pricing and surcharges to keep pace with volatile fuel costs.