According to the invention, a rear portion of a fuselage of an aircraft contains a fuel cell system, and the aircraft further includes a rear cone which is removably mounted relative to the rear portion of the fuselage so as to form an extension thereof. The rear cone is shaped as a fuel tank for the fuel cell system contained in the rear portion of the fuselage. The rear cone includes at least one housing extending into the fuel tank and configured to receive at least one projecting slide extending from the rear portion of the fuselage.