Aviation is far more difficult to decarbonise than other sectors of the economy, because kerosene is the perfect fuel for planes. It produces enough power to enable planes to fly, yet it is light enough for them to get off the ground and cross the world.

Alternatives are thin on the ground; batteries are too heavy, clean hydrogen power is in its infancy, while Sustainable Aviation Fuel - or SAF - is expensive and in short supply. Although the Government has a "SAF-mandate", only 22% of all jet fuel supplied by 2040 will have to be sustainable.

New airliners are more fuel-efficient than ever before, and both routes and air-traffic control are being optimised. But if growth outpaces efficiencies, greenhouse gas emissions will continue to rise.

And passenger demand is back at pre-pandemic levels. In 2024 the UK was the third largest market in the world for flights.

In the absence of any immediate solution, should we fly less, if at all? How realistic and affordable are slower alternatives like the train? Could passengers be penalised for taking more than one return flight a year? And should the Government rather than individuals be taking responsibility for change?

Presenter: Ben Ansell

Contributors:

Rethink is a BBC co-production with the Open University