Higher fuel prices are testing how badly consumers want to travel this summer, whether flying or driving.

Airfare hasn’t been this high since May 2022, when airlines stumbled out of the pandemic with aircraft and employee shortages to face hordes of consumers ready for “revenge travel.” Gasoline is above $4 a gallon and could get closer to $5 a gallon this summer, AAA warned this week.

Jet fuel prices doubled in the span of less than three months this year after the U.S. and Israel attacked Iran, kicking off a conflict that has left a key shipping channel effectively closed.

Domestic round-trip airfares in April averaged $623, the highest in nearly four years, according to data from the Airlines Reporting Corporation, which tracks travel agency ticket sales. Jet fuel is the second-biggest expense for airlines after labor, and carriers say they are increasingly passing those costs along to customers.

Separately, airlines are also trimming their growth plans because of higher fuel costs. Even if a route isn’t cut, fewer flights on certain routes means that customers will have fewer seats to choose from and, with demand robust, that could drive up prices even more.

Spirit Airlines, the most famous budget carrier in the U.S., shut down earlier this month, and partially blamed jet fuel prices for its failure to emerge from near back-to-back bankruptcies. It was the biggest U.S. airline collapse in decades. Other airlines swooped in to snatch up those customers in the aftermath, but the carrier’s demise removes a main purveyor of low fares.

The fuel spikes have set the stage for higher fares and more expensive gas station visits this summer. The start of the peak travel season Memorial Day weekend will be a taste of how much travelers will shell out to fly while everything from groceries to clothing has become more expensive this year.

The Transportation Security Administration said it expects to screen 18.3 million people between Thursday and next Wednesday, compared with the 18.5 million it saw over a similar period last year.

So far, airline executives said, customers are still booking, and executives are optimistic about the summer travel season. They’ve also said they’re expecting a boost from the FIFA World Cup, which will be held in June and July in the U.S., Canada and Mexico, and from major concerts such as Harry Styles’ residencies in Amsterdam and London this summer.

United Airlines said it expects to carry 53 million travelers between June and August, up 3 million people from last year. American Airlines has forecast 75 million customers between May 21 and Sept. 8, after Labor Day, topping its previous record, in 2019.

Travelers can still find deals if they’re flexible, said Kyle Potter, who runs the Thrifty Traveler website. He recommended using tools such as the “Explorer” tool in Google Flights that allows users to look up destinations by the length of trip and by month in a map view.

He also suggested flyers consider traveling on a Tuesday or Wednesday, when fares and traffic are often lower.

“That, in many cases, can save you hundreds of dollars per ticket, and multiply that by a family of four,” he said.

He had a simple message for travelers sitting on piles of frequent flyer miles.

“Now is the time to use your miles or your credit card points or both,” he said, warning that miles can end up devalued. “What are you waiting for? I think a lot of people hoard their miles because they want to go to to Europe in 2027.”

— CNBC’s Contessa Brewer contributed to this report.