The emergence of leaders favouring fossil fuels, such as US President Donald Trump, and recent regulatory rollbacks, are "obviously a setback... it does imperil success on the 2050 horizon", Marie Owens Thomsen, IATA's senior vice president sustainability, told reporters.

"But I don't think it's going to halt or reverse progress. I think it will just slow progress," she said at the IATA annual industry conference in India.

UN aviation agency members, from the International Civil Aviation Organization (ICAO), have set the year 2050 as their goal for achieving net-zero carbon emissions for air travel -- an industry often criticised for its outsized role in climate change.

The air transportation industry has faced growing pressure to deal with its contribution to the climate crisis.

Currently responsible for 2.5 percent to three percent of global CO2 emissions, the sector's switch to renewable fuels is proving difficult, even if the aeronautics industry and energy companies have been seeking progress.

To achieve net-zero emissions, airlines rely on non-fossil sources known as Sustainable Aviation Fuel (SAF).

IATA members preceded ICAO by a year, at their 2021 General Assembly, in setting this ambitious goal, which requires colossal investments.

But SAF fuels are still three to four times more expensive than petroleum-based jet fuel.

Washington's new Republican administration is also however supporting the development of fossil fuels, in contrast to the preceding Democratic one of Joe Biden.