German airline Lufthansa will cut 20,000 European short-haul flights over the summer, saying soaring fuel prices have made many journeys "unprofitable" for the firm.

Jet fuel has doubled in price since the start of the US-Israel war with Iran as the conflict has slowed its production and transportation across the Middle East.

Several airlines, including KLM-France and Delta, have also temporarily cut some flights while others have raised ticket prices as they pass on expenses to customers.

Analysts have warned that travellers should expect further ticket price rises and more cancelled flights as the conflict continues.

The Gulf is a major source of aviation fuel, accounting for about 50% of Europe's imports. The bulk of it comes through the Strait of Hormuz, which Iran has effectively closed in response to US and Israeli attacks.

Lufthansa said on Tuesday it would save roughly 40,000 metric tons of jet fuel through its flight cuts, the majority of which will come from the closure of its CityLine service.

It said this means it will temporarily stop flying to and from Heringsdorf, Cork, Gdańsk, Ljubljana, Rijeka, Sibiu, Stuttgart, Trondheim, Tivat, and Wrocław.

The firm will either refund affected passengers or book them on to alternative flights with one of its other airlines – SWISS, Austrian Airlines, Brussels Airlines, and ITA Airways – where possible.

Some of the flight cuts could become permanent. Lufthansa said it was reviewing its whole European schedule and would release more details later in April.

Shortage concerns

The International Energy Agency warned last week that Europe could run out of jet fuel in weeks, though the UK government and airlines say they are not seeing a disruption in supply.

The EU said on Wednesday it will set up a fuel observatory to track EU production, imports, exports and stock levels of transport fuels to identify potential shortages. 

It said it hoped this would "mitigate the impact of high fuel prices and possible fuel shortages on the EU aviation sector".

Lufthansa said on Tuesday it was cutting down its European network, but that passengers will "continue to have access to the global route network, particularly long-haul connections".

"However, due to the increase in jet fuel prices, this will be achieved significantly more efficiently than before."

Tuesday's announcement comes after it said last week it was accelerating the closure of CityLine, retiring 27 aircraft, due to "significantly increased" fuel prices and "additional burdens from labour disputes".