Assessing the magnitude of detours faced by cargo flights: An empirical analysis

It has largely been assumed by both scholars and experts that planes fly the shortest route. However, due to natural, technical, geopolitical and social reasons, virtually no flight follow the shortest route. This paper assesses the lengthening of distance flown by cargo flights. The analysis is based on a comparison between shortest-route distances and actual distances flown by commercial cargo flights all over the world. The former is computed from the latitude and longitude of origin and destination airports. The latter is calculated in a Geographical Information System based on a one-week set of flights traces bought from FlightRadar. We have considered 12,287 flights operated by 49 cargo airlines. It is found the average detour is of +6.3% and shortest flights are proportionally more affected than longer flights, notwithstanding more uncertainties related to the actual distance of part of the longest flights due to poor coverage over the oceans and some inner lands. Detours have several implications: they often mean higher costs and more environmental adverse impacts; they challenge the assessment of flights’ horizontal efficiency if detours are inevitable; and they raise the robustness of numerous methods developed by scholars (including fuel and emission assessment, and interaction models).