Heathrow has long argued the expansion is needed to help it keep up with rival airports in Europe, which handle less passengers with more runways, with the airport's boss saying a "clear steer" was needed from the government by the end of 2025.

The aviation industry is banking on sustainable aviation fuels to slash carbon emissions, and is also exploring planes driven by electric and hydrogen power. Yet, full-scale commercial application of

British finance minister Rachel Reeves is expected to back the expansion of Heathrow Airport on Wednesday, turning to the country's most controversial infrastructure project in her hunt for economic growth.