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.
On Wednesday, analytics firm Cirium released data showing that airlines have cut 13,000 flights globally in May.
However, the travel agents' trade body Advantage Travel Partnership said the cancellations were marginal overall - about 1% - and UK flights to summer sun destinations were unaffected.
Many airlines that serve the UK have said they plan to operate fewer flights.
They include:
The following companies have said they don't plan to change their schedules:
While some airlines have cut back on the number of flights to save money, others have said they will start charging more or will put up charges for luggage.
These include:
Overall cancellations will be a very small proportion of the millions of flights in and out of the UK, says Rory Boland, travel editor at consumer publication Which?. Airlines are likely to target cancellations on routes where there are multiple flights a day to make it easier to put passengers on a different flight.
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, but it is not standard practice.
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 pass 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 agree deals in advance that help them lock in a lower price, but longer term they will be paying more for fuel.
The biggest rises in fares have been on long-haul routes via Asia, that have been forced to adapt their flight paths to avoid flying over the Gulf.
Flights from London to Melbourne in June now cost 76% more than last year and a flights to Hong Kong are up 72%, according to consultancy Teneo.
"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.
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.
Spain's industry and tourism minister said on 27 April that people should buy airline tickets as soon as possible in case fares are increased to cover higher jet fuel costs.
Jordi Hereu told Spanish newspaper Expansion: "What we're recommending is that people buy their tickets now because it's true that (airlines) are currently using kerosene that was purchased some time ago, and therefore there's an element of price fluctuations involved."
If your flight is cancelled the airline must 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 food and hotel accommodation.
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 extra compensation.
Airlines are currently pushing for more clarity over whether fuel shortages caused by the current conflict 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 if your package holiday travel is disrupted your tour operator should extend your stay, offer you an alternative holiday, or refund you for the holiday, says Boland.
Correction: this article has been amended to remove references to Air Asia and Vietjet as they do not currently fly to the UK. References to Air New Zealand have also been removed as it does not fly directly to the UK, but offers connections through its partners.
