The price of flights has been rising since the start of the conflict in the Middle East, a worry for anyone planning a summer holiday.

Some airlines are also cutting back the number of flights they are operating, which could mean travellers facing changes to their plans.

Many airlines that serve the UK have said they plan to operate fewer flights.

They include:

• KLM
• Air Asia
• Air Canada
• Air New Zealand
• Asiana Airlines
• Delta Airlines
• KLM
• Lufthansa
• SAS
• Vietjet

The following companies have said they don't plan to change their schedules:

• British Airways owner IAG
• EasyJet
• Jet2Holidays

While some airlines have cut back on the number of flights to save money, others have said they will start charging more per passenger or will put up charges for luggage.

These include:

• Air Asia
• Air France-KLM
• Indigo
• Pakistan International Airlines
• Thai Airways
• Turkish Airlines-Sun Express
• Virgin Atlantic

Some airlines are cutting flights and raising prices, including:

• Air Asia
• Air New Zealand

Rory Boland, travel editor at consumer publication Which?, says overall cancellations will be a very small proportion of the millions of flights in and out of the UK, and the changes will be targeted on routes where there are multiple flights a day so that passengers can be rebooked on to an earlier or later flight.

But some passengers may find they are bumped on to a next-day flight, disrupting their holiday plans.

Airlines cannot up the price once you have bought your ticket.

Low-cost Spanish regional airline Volotea has come under fire for saying it will add a surcharge to tickets it has already sold and is being challenged by local consumer rights groups.

An airline or tour operator could only raise the price post-sale if they had a specific caveat written into the terms and conditions, says independent consumer commentator Jane Hawkes.

Airlines are more likely to raise future prices, including for hold baggage or other extras, she says.

However, when it comes to package holidays, tour operators can add up to 8% to the cost of your deal after you've booked, based on a "significant rise in fuel costs", says Boland. But Which? found most operators were promising not to add surcharges this year.

A lot of the industry's jet fuel supplies come from the Gulf region, and most of it passes through the Strait of Hormuz, which has effectively been closed to shipping since the start of March.

Airlines are not physically running short of fuel currently, but there have been warnings of potential shortages by the summer if the conflict continues.

In the meantime the squeeze on supply has pushed up the price of jet fuel sharply - it roughly doubled during March and the first half of April.

Airlines do hedge prices, meaning they agree deals in advance that help them lock in a lower price. So they will not be facing an immediate doubling in fuel costs. But over the longer term they will be paying more for fuel.

The biggest rises in fares have been on long-haul routes via Asia, with flights from London to Melbourne in June now costing 76% more than last year and a flight to Hong Kong is up 72%, according to consultancy Teneo.

That is because the Middle East conflict has forced airlines to reroute traffic to avoid flying over the Gulf. Taking a longer route uses more jet fuel, so airlines are having to buy more as well as paying a higher price for it per tonne.

European air fares have not spiked yet, says Boland.

"There's no right or wrong," says Jane Hawkes. It could pay to wait for last-minute deals, or you might want to seize the moment now. She doesn't expect prices to fall over the rest of the year, however, because airlines still need to cover the increased costs.

"I don't see any quick remedy coming along," she says. "I think this year passengers just have to be prepared to take the hit."

She suggests being flexible over where and when you travel, including considering switching to road or rail or holidaying in the UK.

Book insurance and check your policy covers you for travel disruption, she adds.

And make sure you have a "contingency pot". Even if your holiday operator or airline is supposed to cover any disruption, you may need to pay upfront and claim it back later, which can take months, she warns.

If you have booked a flight and it is cancelled the airline is obliged to get you to your destination or offer a refund.

If you are delayed more than a couple of hours the airline is required to provide or pay for food and hotel accommodation.

• Your rights if your flight is delayed or cancelled

That is in ordinary circumstances. In cases of war, weather, or other situations that are beyond an airline's control, they do not have to offer compensation.

Airlines are currently pushing for more clarity over whether fuel shortages caused by the current conflict, and a knock-on effect on prices, would count as "extraordinary circumstances".

If you have booked your accommodation separately the airline is not required to compensate you for any days you have missed out on.

But you have far better protection if you book a package holiday, Boland says. For example, if a flight is cancelled a tour operator should extend your stay or offer you an alternative holiday, and if it can't, it will need to refund you in full for the whole holiday.