The Chinese air transport system has witnessed an important evolution in the last decade,with a strong increase in the number of flights operated and a consequent reduction of their punctuality.In this contribution,we propose modelling the process of delay propagation by using complex networks,in which nodes are associated to airports,and links between pairs of them are assigned when a delay propagation is detected.Delay time series are analysed through the wellknown Granger Causality,which allows detecting if one time series is causing the dynamics observed in a second one.Results indicate that delays are mostly propagated from small and regional airports,and through flights operated by turbo-prop aircraft,These insights can be used to design strategies for delay propagation dampening,as for instance by including small airports into the system’s Collaborative Decision Making. The Chinese air transport system has witnessed an important evolution in the last decade, with a strong increase in the number of flights operated and a consequent reduction of their punctuality. In this contribution, we propose modeling the process of delay propagation by using complex networks, in which nodes are associated to airports, and links between pairs are them are assigned when a delay propagation is detected. Delay time series are analysed through the well known Granger Causality, which allows detecting if one time series is causing the dynamics observed in a second one .Results indicate that delays are mostly propagated from small and regional airports, and through type by turbo-prop aircraft, These insights can be used to design strategies for delay propagation dampening, as for instance by including small airports into the system’s Collaborative Decision Making .