The design and evaluation of aircraft air conditioning systems with an air cooling cycle are being considered. Output of equation of heat balance used in determination of load on conditioning system is given. Particular attention is paid to the thermal design of cabins in cases of using panel systems. Recommendations are given on the choice of the structural diagram and required parameters of the cooling system of the air cycle, including taking into account the humidity of the cooled air. Limits of aircraft air cooling systems operability are determined depending on aircraft flight altitude and speed.