A method for constructing at least two fleets of aircraft of different families for which each aircraft has a front part comprising windows, a framing of the windows and a windshield front fairing, comprising, for each aircraft, constructing a module composed of the framing of all of the windows allowing outward visibility from the cockpit and of the windshield front fairing whose form is identical and constant for all the aircraft of the fleets and independent of a form of the fuselages thereof, and constructing a section of fuselage of which at least a part of an edge of the fuselage is of a form identical to an edge of the module, such that the module can be assembled directly with the contiguous fuselage section, whatever the aircraft of the fleets.