Much oil-market commentary on the 2026 Iran war still begins with crude benchmarks. For aviation, that misses the binding constraint. The problem is not only the price of crude oil. It is the availability of jet fuel: a refined-product shortage created by blocked shipping, damaged refining capacity, incompatible crude slates, and inventory buffers under drawdown. I come to this question from an unusual angle: I have spent the last two months tracking how this shock transmits through humanitarian supply chains, and jet fuel is where the energy story and the humanitarian story converge.
Since 28 February, the Strait of Hormuz has not returned to normal commercial operation. Traffic collapsed to single digits in the first week and has remained far below normal, fluctuating under conditional passage rather than returning to ordinary commercial flow. Insurers are pricing the security regime, not the diplomatic calendar.
The supply gap
Kpler estimated, in reporting by The Air Current and Reuters, that the Hormuz closure has cut off nearly 21 per cent of total global seaborne jet fuel supply. Europe has lost approximately 300,000 barrels per day of imports. By some estimates, Kuwait alone accounted for 10 to 15 per cent of global seaborne jet fuel trade in 2025. Global jet fuel exports have fallen more than 60 per cent since early March, according to Argus, to under 700,000 barrels per day.
As of late April, the damage extended beyond maritime disruption. Reuters reported that nearly 1.9 million barrels per day of Gulf refining capacity had been shut by 10 March, with further disruption from attacks, precautionary closures and reduced runs. Saudi facilities including Ras Tanura, Bahrain’s Bapco/Sitra refinery complex and the UAE’s Ruwais have all been affected. Part of this system requires repair and requalification, not just price clearing.
The crude-slate mismatch
Jet fuel sits in the middle-distillate part of the barrel. The issue is not that sulphur makes better jet fuel. It does not. The issue is crude slate and refinery configuration. Many Gulf and Asian refining systems are built around medium-sour Middle Eastern grades that, after hydrotreating and conversion, yield materially more middle distillates than light-sweet replacement barrels. Reuters reported that Asian refineries forced to process lighter replacement grades are producing less diesel and jet fuel. Vortexa estimates Middle East crudes yield roughly 60 per cent middle distillates versus about 40 per cent for WTI. Refinery tuning can improve yields at the margin, but it cannot quickly replace the lost medium-sour system at global scale.
S&P Global reported that the United States was Europe’s largest refined-products supplier overall in 2025 but only the seventh-largest jet fuel supplier, at approximately 3 per cent of European jet inflows. Even as the dominant refined-products exporter, the US punches far below its weight in jet fuel because of the crude-slate and configuration constraint.
Substitution is happening, but not fast enough
Some replacement flows are arriving. Europe has pulled record jet fuel inflows from the United States and Nigeria. But those volumes cannot replace the Gulf system at speed. China curtailed exports in March. Thailand, South Korea and Japan imposed their own constraints. China has since approved limited May volumes, but those remain less than half last year’s monthly average. The substitution pathway exists, but not at sufficient scale or speed to restore the pre-war system.
The allocation window
Much of the jet fuel at European airports in recent weeks left the Middle East before the war began. The in-transit and fuel farm buffer has been approximately six to eight weeks deep. That buffer is now being drawn down. IATA has warned that Europe faces summer flight cancellations. Europe faces end-May and June cancellation risk if replacement supply falls short. Platts CIF Northwest Europe jet fuel was assessed at $1,765 per metric ton on 30 March, more than double pre-war levels.
Beyond passenger travel
The aviation shock does not stay within the airline industry. Passenger aircraft carry belly freight, and when airlines cut frequencies, cargo capacity falls with them. Reuters reported that the conflict cut global air-cargo capacity by 22%, with Asia–Middle East–Europe capacity down 39%. When a European airline cuts a route to manage fuel allocation, it is also cutting the belly freight capacity that moves medical supplies to Port Sudan, the only functioning international port in a country where 25 million people need humanitarian assistance. The fuel allocation decision made at an airline operations desk in Frankfurt has a direct consequence in a displacement camp in Darfur.
A Mercy Corps report published this month traces this transmission across Sudan, Somalia, Ethiopia, Pakistan, Myanmar and Lebanon. Air freight costs for Afghanistan nutrition supplies that would normally have moved overland through Iran hit $240,000 for a single delivery. Save the Children reported $600,000 in medicines for Sudan stranded due to shipping disruption. These are not abstract supply-chain metrics. They are medicines that did not arrive and children who were not treated.
The Hormuz shock is a crude crisis in the aggregate. But for aviation, the binding constraint is narrower: a jet fuel gap created by lost Gulf exports, constrained refinery systems, incompatible replacement barrels, and inventory buffers under drawdown.
