Air transport, which has existed for more than 100 years, is responsible for 3% of global CO2 emissions. Although aircraft are infinitely more efficient (80%) than in the 1960s, the United Nations' Sustainable Development targets call for a reduction in emissions by half by 2050, a figure that airlines have accepted and are even seeking to improve. In fact, the European Climate Act aims to achieve a carbon-neutral European Union - zero net emissions of greenhouse gases - by that date. And experts are confident that aircraft will be 100% electric in 20 years.