10-20% efficiency is enormous considering fuel is by far the dominant lifetime cost of operating an aircraft. New fuels (SAF) and the technology to use them ha

10-20% efficiency is enormous considering fuel is by far the dominant lifetime cost of operating an aircraft. New fuels (SAF) and the technology to use them have been developed for less. This is all to say nothing of the continuous work done over decades now to make aircraft more efficient; as these effects compound, intuition says that returns would start diminishing, so 10-20% is even more impressive.