Abstract: The invention relates to an aircraft air conditioning system with at least one compressor, comprising a first conduit which is connected with the pressure side of the compressor and in which one or more cooling means provided downstream of the compressor are arranged for cooling the air compressed in the compressor, and comprising a second conduit designed as bypass conduit, which likewise is connected with the pressure side of the compressor and is arranged such that it conducts at least part of the air compressed in the compressor in a bypass around at least one of the cooling means, wherein a throttle means is arranged in the bypass conduit, by means of which the mass flow of the air conducted through the bypass conduit can be varied, and that a unit (ECU) is provided, which is designed such that it can be operated in a first and/or in a second operating mode, wherein in the first operating mode, when the opening of the throttle means (TCV_H) provided in the bypass conduit (20) is increased, the unit (ECU)