The aeronautical industry is betting on sustainable aviation fuel (SAF) to reduce its carbon footprint, but its high cost slows down its massive adoption. While Iirbus launches the initiative Book and Claim and that IATA, the association of international air transport, deploys the SAF Registrytensions are not lacking in the subject of the distribution of the costs of this ecological transition, which threatens the objective of carbon neutrality set for 2050. The latter seems more complicated than ever to be achieved for the world of aviation.