European tourism faces a tough summer as the Iran conflict and the closure of the Strait of Hormuz squeeze global jet fuel supplies.

Airlines have canceled flights, while the UK is relaxing fuel standards and flight scheduling rules to ease the crunch. The International Energy Agency warned recently that stores could run dry in Europe this month. The US is less exposed, but fuel prices have doubled, and airlines are passing costs on to passengers.

The EU’s energy commissioner told Politico that travel will be disrupted “no matter what happens,” and that the bloc may need to release emergency reserves. JPMorgan, meanwhile, warned investors that stockpiles, although apparently large, are partly inaccessible for technical reasons, creating an “illusion of plenty.”