1. Context

Civil aviation has developed at a steady pace for several decades, correlated with the growth in international trade at a ratio of 3:1. Urban development is also driving this growth: for example, the world's 26 conurbations with more than 10 million inhabitants account for 20% of this traffic, while the 62 conurbations with more than 5 million inhabitants account for 40%.

Technological developments have also contributed to this growth, by constantly integrating both performance and productivity.

Although the increase in air traffic shown in figure 1 is associated with fuel consumption (figure 2...