As the U.S. and Israel's war with Iran squeezes global oil supplies, travelers have valid reasons to worry about the cost and availability of flights as they plan their late spring and summer trips.

The head of the International Energy Agency has warned that European countries could run low on jet fuel within weeks, forcing the continent's airlines and carriers that fly to Europe to significantly reduce flights. Many airlines have already raised checked bag fees or added fuel surcharges as the global price of jet fuel increased from about $99 per barrel at the end of February to as high as $209 a barrel at the beginning of April.

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In a sign of the conflict's ongoing repercussions for travel, Air Canada said Friday it planned to suspend its service to New York's John F. Kennedy International Airport from June 1 until Oct. 25 to lower its fuel costs. Other airlines, ranging from U.S. carriers like United and Delta to Air France-KLM, SAS, Philippine Airlines and and Cathay Pacific in Europe and Asia, have reduced routes and either increased ticket prices or said they would hike them if the war keeps oil from passing through the Strait of Hormuz.

"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.

With airfares and fees on the rise, consumers still can make choices that determine how much of their travel budgets will get taken up by paying to get to and from their destinations.

Act quickly

While consumers may be tempted to see if the war ends before buying airline tickets, the "wait-and-see" approach to booking flights is riskier this year, travel experts say, especially the longer the war goes on and the closer to summer and other peak travel periods it gets.

"Presuming there is a lasting ceasefire — or better yet, peace agreement — it will take a few months for normal levels of jet fuel production and delivery to resume," airline industry analyst Henry Harteveldt, president of Atmosphere Research Group, said.

Iran's reversal on Saturday of its decision to reopen the Strait of Hormuz and President Donald Trump's insistence on maintaining a U.S. blockade of Iranian ports illustrated the shakiness of prospects for oil flowing reliably again from the Persian Gulf and with it, an easing of the price pressure on airlines and their customers.

"My advice to travelers is this: If you find a flight whose schedule fits yours, with a fare you can afford, and on an airline you can at least tolerate, book it," Harteveldt said. "But — and I cannot emphasize this enough —do not book a Basic Economy fare," the cheapest but also the most restrictive airline ticket class.

Along with charging for checked bags and seat selection, most North American airlines do not give refunds or travel credits to passengers with Basic Economy tickets if they don't cancel their trips within 24 hours of purchase. Policies may vary, but spending more for a Standard Economy ticket provides more flexibility, according to Harteveldt.

Paying more up-front for a refundable ticket also prove advantageous because "if the prices start to dramatically change, you can cancel and rebook for the better price," Gilad said.

Travel experts say that for now, longstanding booking guidance offers a baseline for how early to reserve a flight to get the lowest airfare: international flights are typically the cheapest about two to five months in advance, and domestic trips about three to six weeks out.

Last-minute bookings and other situations that typically command higher prices are likely to keep climbing, Gilad said.

"Remember, especially if you're traveling on the major airlines, they're going to have more ability to adjust fares. If you book too close to your travel date, you're going to pay more," he said. "The farther out you can book, the better."

Keep an open mind

Travelers who don't want or need to reach a specific place at a specific time can find it easier to save on airfare. Shifting departure or return dates by a day or two — especially from peak weekends and holidays to midweek — often yields big price differences.

Choosing a different destination also may pay off. A flight from the U.S. may be significantly cheaper to one European city than another. Since budget airlines and trains connect much of Europe, and trains, an airport it cost less to get to can still provide easy access to a lot of other places.

Consumers not set on a certain arrival destination can try tools like Skyscanner's "Explore Everywhere" feature to look for less-expensive options.

Looking beyond the closest airport for departures also can make a meaningful difference. Major hubs tend to offer more flights and lower fares than smaller regional airports.

In some cases, booking a separate short flight or train to a hub will unlock a cheaper long-haul airfare — think Milwaukee versus Chicago's O'Hare International Airport.

Travel light

Sticking to a carry-on bag, when possible, can help avoid the higher fees for checking luggage that many major U.S. airlines introduced recently, including Delta, American, United, Southwest and JetBlue.

If packing light is not an option, plan ahead because airlines typically charge more to add bags closer to departure, especially within 24 hours of a flight.

Redeem your points

While fares are going up, the number of airline points needed for many flights has not increased at the same pace, said Adam Morvitz, CEO of points.me, a loyalty rewards redemption search platform.

Airlines still need to fill seats, Morvitz said, and offering more of them for fewer points is one way to do it.

Customers without enough frequent-flyer miles or credit card points for a round-trip ticket still can redeem their travel rewards for one leg of a journey and free up cash for other travel expenses.

Many travelers redeem points directly through their credit card's booking portal, where they're typically worth about 1 cent each, Morvitz said. Transferring points to airline loyalty programs often unlocks significantly better value because most major credit card issuers partner with a range of airlines.

Take American Express, whose points can be transferred to Air France's Flying Blue program. Travelers who don't want to book with Air France still can use those points with the airline's partner carriers, such as Delta, Morvitz said.

"Points are a form of wealth, and consumers should recognize that those points increase spending power," he said.

Explore travel credit cards

For those new to travel credit cards, sign-up bonuses may yield benefits that can be put to use as soon as this summer. Some bonuses are large enough to cover a flight after meeting a minimum spending requirement.

"Even if you were to travel the entire year, taking one trip per month, you would still earn more points simply by signing up for the card than actually sitting on a seat and flying," Morvitz said.

Points and rewards can add up through everyday spending on groceries, dining and gas. Some cards include perks like free or discounted checked bags.

AP writers Dee-Ann Durbin in Detroit, Mae Anderson in New York and Lisa Leff in London contributed to this story.