航空公司之客貨航班時間帶調整規劃之研究

Abstract

航空產業深受全球經濟景氣循環的影響。尤其景氣呈現下滑時，航空公司若僅減少頻次可能造成更多旅客量與貨量之損失，故在此情況下，可將航班起降時間謹慎納入規劃考量，透過不同航線需求時間之分布狀況，將適當的飛機頻次安排在此航線需求較高的時間帶上。Teodorovic(1988)曾指出航空公司提供適當的飛機頻次與飛機班表可增加航空運輸的載客數，因此在景氣波動下，為維持公司營運利潤，起降時間帶及頻次之規劃即顯得相當重要。 本研究針對客貨兼營航空公司不同景氣狀況下之決策進行分析，考慮時差、航班飛行時間、延遲時間，以及旅客、貨物意願之起降時間，目的地與出發地之活動起始結束時間，此外，因航空公司安排航班過程中無法使所有航班都能滿足旅客與貨主的要求，故修正Koskosidis et al. (1992)之研究，提出票價折讓函數與貨運費率折讓函數，即當該航班時間規劃愈能滿足旅客與貨主之要求時，其旅客承載率與貨物載貨率也愈高，在此狀況下則不予折讓，反之則給予不等的折讓數。並考量不同航線頻次需求狀況進行規劃，以最大化航空公司利潤為目標，構建一數學規劃模式以決策航空公司最佳時間帶以及最適頻次。進一步本研究透過不同時間帶配置方案，提出僅考慮尖峰時間帶之部分市場制時間帶配置方案，並採以權重法與解析性兩種方式討論航空公司利潤差異，權重法採各時間帶利潤佔航空公司總利潤比重作為權重值，以該時間帶利潤貢獻程度求取航空公司願意競價金額，而解析性則是透過分析不同順位時間帶之利潤與成本，以推演各順位時間帶可競價金額之區間，及航空公司對各順位時間帶最大競價金額，並根據此兩種方式求算各家航空公司總合利潤，既而與目前歷史優先權配置方式、完全競價方式作一利潤的比較分析。最後，蒐集實證分析中之相關資料，以驗證本研究模式在實際應用之可行性。 研究結果顯示，利用客貨航班時間帶調整規劃模式，可在最大航空公司利潤下求得最佳客貨運時間帶位置分佈與最佳頻次，而透過景氣波動下之探討，驗證採用最適時間帶配置方式較未採用時間帶配置方式可在景氣好轉時獲取更大利潤，並在景氣下滑時節省較多成本以維持營運。此外，機場透過部分市場制時間帶競租方案之決策方式，雖使部分航空公司總合利潤較歷史優先權方式減少利潤，但透過競價方式卻可促使航空公司對時間帶作較充分且有效率的使用。在部分市場制時間帶配置方案中以權重法對於航空公司較有利，原因在於權重法採用該時間帶之利潤貢獻度，對利潤貢獻較高之時間帶以較高金額競價，而解析性方式採各順位時間帶之利潤與成本推演出競租金額，可能使利潤貢獻度高的時間帶未採以高競價金額致喪失此時間帶，此可提供各家航空公司規劃各航班於最適時間帶與機場民航單位研擬時間帶配置方案之參考。

Abstract The global economics affects airline market deeply. Especially when economics comes to a slump situation, airlines may encounter losses of both passengers and cargo if they just considered reducing flight frequency. Teodorovic (1988) pointed out that “proper insight passengers’ transportation demand and the distribution of this demand over time can increase the number of air transportation passengers by offering an adequate number of flights at suitable times.” Hence, it is important for airlines to plan the optimal flight arrival and departure time and flight frequency to maintain business profit under changing economic situation. This study analyzes decisions on flight departure time zones under different economic situations for airlines which operate air services for both passengers and cargos. Factors considered in the study include time lag, flight flying time, flight delay, preferred arrival and departure time of passengers and cargos, the beginning time and the ending time in destination and origination, etc. Since airlines couldn’t make all flights departure time meet the demand of passengers and cargo owners. The study introduces discount functions for tickets and freight charges for flights with various schedule delay. The more the flight departure time satisfies the schedules of passengers and cargo owners, the higher the load factor of the flight. The study further formulates a model using mathematical programming method by maximizing airlines’ profits to find out the optimal departure time zone and frequency for all flights. Furthermore, the study proposes partial-market time-slot allocation scheme using Weighted approach and Analytical approach and estimate their difference in airlines’ profits. The Weighted approach uses the ratio of the profit of individual time zone divided by total profit of airlines as weights to determine the auction price of different time zones. The Analytical approach deduced the range and the maximum value of individual time zone through analyzing profit and cost of the time zone. The study further estimates and compares the total profits of two methods. Finally, the study demonstrates a case study and collects necessary data to show the feasibility of the model. The results of the study show that the model can determine the optimal departure time-zone and flight frequency which maximizies airlines’ profit. Time-slot allocation scheme is better than non time-slot allocation scheme under different economic situations. Furthermore, although the amount of total profits for all airlines is smaller if airport authority adopts partial-market time-slot allocation scheme rather than historic precedence allocation scheme. Nevertheless, it can enable airlines to use time-slot more efficiently through auction scheme. For partial-market time-slot allocation scheme, airlines earn more profits using Weighted approach than analytical approach.