Flying from London to Amsterdam or Barcelona might soon cost noticeably more — and the reason isn't fuel prices or airport fees. It's Britain's sustainable aviation fuel (SAF) mandate, which airlines warn could tack roughly $34 (£25) onto a shorthaul ticket by 2030.
The rules already require SAF to make up 2% of jet fuel supplied in the UK, rising to 10% by 2030 and 22% by 2040. The flashpoint is a cap, kicking in from 2027, on SAF made from used cooking oil and animal fats — currently the most common and cheapest type. The government wants to push airlines toward newer synthetic fuels instead. The catch: those advanced fuels barely exist at commercial scale, and several production facilities years away from opening.
If carriers can't buy enough qualifying fuel, they'll face penalties for missing the mandate — and those penalties will land in the fare. WPI Economics estimates the mandates could add about $2.7 billion a year to airline fuel bills by 2030. Airlines and industry voices aren't shy about the absurdity: IATA's Willie Walsh has argued that mandating a product nobody can supply delivers no environmental benefit at all, and has accused fuel suppliers of using European mandates to charge compliance surcharges. SAF made up less than 1% of global airline fuel in 2025 and costs several times more than conventional kerosene.
The UK has committed more than $270 million to boost domestic SAF production, but supply still lags well behind the timetable. The author of the source piece suspects airlines are sounding the alarm now in hopes of a delay, with fuel market disruption from the Iran war strengthening their case. On budget carriers like Ryanair or Wizz Air, where base fares can be under £30, a $34 compliance cost could roughly double the ticket price.
Why should travellers care? Because this isn't a distant 2040 problem — the cooking-oil cap arrives in 2027, and fare impacts could show up well before the 2030 target. If you fly shorthaul in and out of the UK with any regularity, this is a genuine line-item change to your travel budget.
There's a fair debate to be had: decarbonising aviation won't be free, and higher fares may be a legitimate environmental tradeoff. The frustration for passengers is paying more for exactly the same flight — no difference onboard, just a bigger total at checkout. The honest version of this policy would say so outright. The pragmatic hope is that either SAF production scales up fast, or the government adjusts the timeline before penalties start flowing through to fares.
