Airline stocks have been among the big losers since the war began.

More than 37,000 flights to and from the Middle East have been cancelled since 28 February, according to ​data from Cirium.

Jet fuel prices vary by region, but averages during the war to date are up around 80%. 

In Europe, shares in British Airways owner IAG are 14% down in the year to date.

Many of its main US rivals, tipped for further declines when the US Stock Exchange opens later, were already down by more than that figure at close of business on Friday.

US suffers more than Europe

The price of airfares for European carriers is under little immediate pressure because they hedge their fuel costs in advance to help keep fares and earnings guidance as stable as possible.

In most cases, up to 85% of their respective fuel costs are effectively locked in – the biggest single bill that airlines face after employment costs.

However, US carriers have largely stopped the practice over the course of this century, leaving them under big pressure to raise ticket costs to compensate for higher fuel bills.