What has happened?

The war in the Middle East has led to severe problems around the supply of oil as the vast majority of ships have been unable to navigate through the strait of Hormuz. As a result, the price of oil has jumped to a high of $119 (£88) a barrel in March, from $72 (£53) before the war. Prices fell sharply on Friday however to $89 (£66), after Iran said Hormuz would reopen for the duration of a 10-day ceasefire in Lebanon.

The Airports Council International (ACI) Europe, the airports’ trade body, has said that unless stable supply begins within three weeks, there will be shortages of jet fuel and flight cancellations will be inevitable.

“There’s a growing chance that leisure flights could start being cancelled from May if carriers are unable to source enough fuel from other producing nations,” says Susannah Streeter, the chief investment strategist of investment firm Wealth Club.

What if my flight is cancelled?

If your flight leaves from a UK or EU airport or arrives into them on a UK or European airline, you must be given a refund or an alternative flight. If the cancellation happens less than two weeks before departure, then you may be entitled to compensation as well as a refund or replacement flight. The amount of compensation is based on how far you are travelling.

Jane Hawkes, a consumer rights commentator, says that airlines could cancel on the day of departure. “In a situation like a fuel shortage, where circumstances can shift quickly, passengers may receive limited warning as airlines aim to keep services running for as long as possible before making final calls.”

If you are stranded, the airline is obliged to provide meals, transport and accommodation until it can fly you to your destination.

Passengers on airlines that are not covered by the UK and EU rules should check the terms and conditions of the flight. This will often include a replacement flight or a refund for a cancellation, although compensation varies.

What if I am on a package holiday?

People on package holidays are protected under the Package and Linked Travel Arrangements. The travel operator is responsible for the whole trip and if the flight element is cancelled, they have to offer an alternative holiday of the same value or a refund.

“The package travel regulations are the strongest protection that holidays have,” says Rory Boland, the editor of Which? Travel. “Importantly, your provider is also responsible for getting you home if a fuel shortage should disrupt your return flight.”

This means that you do not have to pursue separate refunds for each part of the holiday.

However, holiday providers can increase costs in the case of fuel price rises. Boland said the surcharge can be up to 8% but this detail must be in the terms and conditions. “If they want to charge you more than 8% you have the right to cancel with a full refund,” he says.

And if I arranged it myself?

If you have booked the different parts of the holiday yourself, paying for flights and accommodation separately, you are in a weaker position than those who have a package deal.

If your flight is cancelled, you will still be entitled to a refund or another flight, but there is no automatic right to claim refunds on the hotel or other expenses.

Matt Gatenby, a partner at the law firm Travlaw, says it is possible that travel insurance will cover the costs of the hotels. However, policies differ and it is important to go through the terms and conditions so you are clear about your rights.

If the airline cancels the flight, they will not be responsible for any other losses, such as the hotel. However, your accommodation may offer last-minute or late cancellations.

“Travel insurance is there to fill the gaps that airlines don’t cover. While airlines must refund or replace your flight, they won’t usually cover knock-on costs like hotels, car hire or other prepaid bookings,” says Hawkes.

What about credit card protections?

If you have bought your flight tickets on a credit card, you will be covered under section 75 of the consumer credit act (once the purchase was more than £100) which holds the card provider jointly liable in the event that a company fails to deliver items or if there is some other breach of contract.

However, Gatenby says that it should be the last port of call and may not be necessary if the airline does what it is supposed to do. “If the airline or tour operator has refunded and that is the extent of their liability, there isn’t anything left to do,” he says.

If your flight is cancelled but you also have a hotel booking, you would not be able to make a section 75 claim for the accommodation costs, according to UK Finance, as the hotel would still be able to honour your original booking even if you couldn’t make it.

And if you have not yet booked your holiday?

Adopt a “belt and braces approach”, says Hawkes. “Book a package holiday using a credit card and take out comprehensive travel insurance, not just a token policy so as to tick your pre-holiday to do list.”

If booking accommodation yourself, try to get one which allows for cancellation as close to the date of arrival as possible, although this often costs extra.

And brace yourself for the possibility of delays if coming back from some European airports as travellers have reported waiting up to three hours at border checks due to the EU’s new entry-exit system (EES). If you miss a flight because of long delays, even if you arrive at the airport on time, it’s unlikely that an airline will offer you another flight for free or pay compensation, according to the UK Civil Aviation Authority. Some passengers have found themselves having to pay substantial extra amounts to get home.

Are there some airlines that will be better to book with than others? And is it better to fly to the big hub airports than smaller local ones?

More than ever, passengers may want the reassurance of an airline that is not going to go bust. Most big airlines are hedged on fuel – ie, not yet seeing their costs double in the oil shock – and all airlines usually make hay in the summer. Longer term, or longer haul, the airline’s bottom line may become a consideration.

Fuel or aviation experts don’t want to hazard a public guess at what may dry up first. Bigger airports such as Heathrow or Barcelona are more likely to have multiple sources of fuel such as pipelines as well as trucks, but airlines also have different contracts and suppliers. Hub airports may have more departures to the same route – meaning more scope to cancel and accommodate passengers on a different flight.

Within Europe, airlines are likely to be able to tanker – ie carry enough fuel for return or onward trips – even if local sources of jet fuel dry up. That again may not apply to long-haul trips, with some Asian countries already reporting problems.

Is it better to book now or wait?

In general, fares go up closer to departure date, and the very cheapest seats are most likely found when flights are first on sale. That said, there are few bargain summer flights to popular destinations left – and analysts have suggested some airlines may yet have to discount if nerves deter too many people from booking.