BBC News - Ben Morris
On a typical day 1,300 planes take off and land at Heathrow Airport, and keeping that going requires around 20 million litres of jet fuel every day.
Heathrow Airport itself does not buy and sell fuel, that's down to the airlines and their suppliers.
However, it does have to think about the infrastructure, allotting space for storage and pipes, and making sure the airlines and fuel firms have everything they need.
But, when it comes to fuel, airports around the world are having to have a major rethink.
In the UK, under the government's Jet Zero plan, by 2040 the UK aviation industry has committed to achieving net zero carbon emissions.
The US aviation industry plans to reach net zero by 2050. The European Union has a similar goal.
