A method for reducing the consumption of fuel by passenger aircraft in an air transportation system which includes at least two airports between which there is at least one flight route, having the following steps: a) retrieving flight data F relating to the airports from a first memory; b) determining a flight route along which a number of n≥2 flights, whose departure times are in a first time window T1 by means of n first passenger aircraft are carried out, from the flight data F; c) determining a total number of passengers Z of the n flights and storing the total number of passengers Z in a second memory; d) selecting m≤n−1 second passenger aircrafts with a total capacity of Gm≥Z for carrying out m flights; e) retrieving passenger data P of the n flights from a third memory and storing the passenger data P in the second memory; f) configuring equipment features Mm of the m second passenger aircrafts taking into account the passenger data P; g) carrying out the m flights along the determined flight route with the m second passenger aircrafts with departure times in the first time window T1.