One of the little known deviations in UK and EU law since the UK’s departure from the EU in 2020, is the rule around where airlines can and should refuel for their journeys. In an attempt to force airlines to use more expensive sustainable fuel sources (SAF), the EU decreed that all airlines must source 90% of the fuel for a given flight from the EU airport that they are departing from. This way, through controlling what fuel the airport can sell, the EU can ensure that planes departing from EU airports have to use the more expensive fuel.
The UK did not go the same way with its legislation, and so does not provide the same restrictions. Passenger jets can typically carry significantly more fuel than they require for a single journey, and so those departing from the UK can choose to “fill up” in another non-EU country where the fuel might be significantly cheaper and more abundant.
But why would this be an issue? Why would jet fuel be cheaper and more abundant than in the EU? Well this comes down to the war in Iran, and the access to the Strait of Hormuz – a major marine shipping lane for fuel destined for the EU, which happens to pass through water controlled by Iran.
So at best your return flight from the EU may be significantly more expensive due to the cost of the jet fuel that the airline needs to source from within the EU. At worst, your flights might be delayed or even cancelled, as supplies of jet fuel within the EU get even tighter and priority decisions need to be made on which flights can continue to operate – and the EU will not be prioritising flights carrying British tourists.