本研究以航空貨運為研究對象，利用解析性的方法分析影響運送過程中儲運成本 的因素，並構建直接運送與轉運兩路線之成本函數，由兩運送路線成本的比較推論在軸輻航 空網路下各航線的貨物應採直接運送或透過空運中心轉運。在模式中可反映貨物時間價值、 起迄點與空運中心之間的流量與空間分布對成本函數與路線選擇的影響。研究結果可由成本 的最小化推導在特定距離與流量下的最適機型，此外並建立航線之臨界流量以作為判斷各起 迄點間貨運是否需經空運中心轉運之指標：而當貨物時間價值增加時，則有利於轉運路線的 選擇。

　　　　　This paper develops a model for deciding whether to route an air shipm ent through a hub or directly to its destination. The logistic cost functions for two yptes of shipping routes ae formulated by considering relevant costs in shipping process and then compared to make the optimal route choice. The model shows how the time value of shipments, route flows and spatial distribution of origin, destination and hub airports affect the shipping costs and route choices. For each link with specific flow and distance, there are procedures in the model to find the optimal type of aircraft which yields the minimunm cost. The paper also identifies critical route flows which decide the optimal routing for freights shipped between origin and destination airports. The sensitivity analysis of the model shows that the routing via a cargo hub will be more necessary when the time value of an air shipment raises.