A method for controlling an aircraft air conditioning system, the method comprising: - controlling a volume flow of recirculation air discharged from an aircraft region to be air conditioned; characterized by the steps: - determining a heating or cooling demand of the aircraft region to be air conditioned, and - controlling a volume flow of compressed air into a mixing chamber of the aircraft air conditioning system such that the heating or cooling demand of the aircraft region to be air conditioned is met, while the volume flow of compressed air into the mixing chamber of the aircraft air conditioning system is minimized, wherein the volume flow of compressed air is a volume flow of cool air exiting an air conditioning unit and hot compressed air supplied to the cool air exiting the air conditioning unit via a bypass line bypassing the air conditioning unit, if a heating demand of the aircraft region to be air conditioned is determined and the volume flow of compressed air into the mixing chamber exceeds a predetermined minimum value: - increasing a volume flow of recirculation air discharged from the aircraft region to be air conditioned into the mixing chamber, - decreasing the volume flow of compressed air into the mixing chamber in dependence on the increase of the volume flow of recirculation air into the mixing chamber until the volume flow of compressed air into the mixing chamber has reached the predetermined minimum value, and - stopping the increase of the volume flow of recirculation air into the mixing chamber, after the volume flow of compressed air into the mixing chamber has reached the predetermined minimum value, as soon as an actual temperature of the mixed air in the mixing chamber corresponds to a set temperature of the mixed air in the mixing chamber, the set temperature of the mixed air in the mixing chamber being associated with the heating demand of the aircraft region to be air conditioned. - controlling a volume flow of recirculation air discharged from an aircraft region to be air conditioned; - determining a heating or cooling demand of the aircraft region to be air conditioned, and - controlling a volume flow of compressed air into a mixing chamber of the aircraft air conditioning system such that the heating or cooling demand of the aircraft region to be air conditioned is met, while the volume flow of compressed air into the mixing chamber of the aircraft air conditioning system is minimized, wherein the volume flow of compressed air is a volume flow of cool air exiting an air conditioning unit and hot compressed air supplied to the cool air exiting the air conditioning unit via a bypass line bypassing the air conditioning unit, - increasing a volume flow of recirculation air discharged from the aircraft region to be air conditioned into the mixing chamber, - decreasing the volume flow of compressed air into the mixing chamber in dependence on the increase of the volume flow of recirculation air into the mixing chamber until the volume flow of compressed air into the mixing chamber has reached the predetermined minimum value, and - stopping the increase of the volume flow of recirculation air into the mixing chamber, after the volume flow of compressed air into the mixing chamber has reached the predetermined minimum value, as soon as an actual temperature of the mixed air in the mixing chamber corresponds to a set temperature of the mixed air in the mixing chamber, the set temperature of the mixed air in the mixing chamber being associated with the heating demand of the aircraft region to be air conditioned.