Abstract: When a large-scale flight delay occurs,it should be meaningful to accurately predict their progress and come up solutions to mitigate consequence.This study predicts large-scale flight delays from the perspective of fixed air-space.A Logistic model is developed based on the number of delayed flights and their cumulative delay time.Considering the number of flights in real-time,the variation of delay time is regarded as parameters in this model.A case study based on observed data of a large-scale flight delay in North China in the afternoon of August 17th,2013 is used to fit the Logis-tic curve.Based on which,the accumulation and dissipation phases of delay are computed to determine respective parame-ters.Finally,the forecasting delays are obtained.The closer to the present time,the higher the accuracy is.Moreover, the maximum relative errors between observed and the forecasted number of delayed flights and the accumulated delay time of flights are 3.9% and 3.6%,respectively.