By analyzing the basic elements of air traffic impedance and referring to the road traffic Bureau of Public Road (BPR) impedance function, an air traffic impedance function model was proposed to study the air traffic impedance problem considering the runway saturation of departure and landing airports, which provided a new research idea for air traffic impedance analysis. The flight data of Nanjing Lukou International Airport-Beijing Capital International Airport (ZSNJ-ZBAA) were used for fitting analysis and model parameters calibration. The results of the model only considering the runway saturation of landing airport were presented separately according to the traffic control situation. Furthermore, the parametric tests were conducted, the fitting performance was compared with the model considering the runway saturation of landing airport in terms of its goodness-of-fit index. Comparison shows that the accuracy of the integrated model is improved by 11.9% without flow control and 16.7% with flow control, which can provide a reference for air traffic management.