AbstractsTransportation

Air transport provides a suitable way of transport for special types of freight such as emergency freight (spare parts, documents), high-value freight (gold, currency, and artwork) and perishables (pharmaceuticals, fresh food, cut flowers) as these products have very short shelf life and benefit from fast transit times. Air transport is also responsible for most of the value added. As stated by Boeing, even though air freight accounts for fewer than 2 per cent of total tonnage transported, it represents almost 40 per cent of aggregate value of total world trade, proving that it is a link of paramount importance for the global supply chains. Descriptive models can aid decision makers in their understanding of the response of global air freight flows to external factors such as the global economy and technological innovation and provide a quantitative underpinning of forecasts and of business cases for investment. Although in the air freight transport business, use is often made of long term forecasts, there is little shared knowledge about which methods should be preferred, and hardly any literature at the scientific level. Transport models were originally developed for passengers and ensuingly applied in freight. Although it is accepted that the four-step transport modelling methodology is a fitting framework for freight, many fundamental differences exist between them such as diversity in decision makers, commodities transported, mode properties, the networks etc. In the particular case of air freight transport, these elementary dissimilarities call for an adaptation of the existing methods, towards a modelling framework better suited for the airborne movement of goods. There lacks a strategic model for air freight flows at the global scale that overcomes the insufficiencies of passenger oriented models. This research contributes to the literature by formulating a model for global air freight demand and network flows. The results of the model are presented in the form of international air freight flows, followed by results on a regional level, sensitivity analysis and validation. The model is found to produce realistic results within the rational range set by observed air freight volumes.