Non-aviation revenues and growth in passengers' traffic: clustering Italian airports

The paper discusses about the relevance of non-aviation revenues (NAR) in Italian airports, in the light of the dynamics of the growth rate of passengers. In particular the study tries to comprehend if similar dynamics in growth of passenger traffic is associated to a similar relevance and incidence per passenger of non-aviation revenues and if this relationship impact on the strategic orientation adopted by airport managers. The study applies a peculiar methodology to compare time series with a single datum in time. Time information is at first synthesised via B-splines fitting, which allows obtaining coefficients that express the shape of each series properly. Comparison of the series with two indicators of relevance and incidence of NAR is then made through fuzzy clustering. The evidence suggests that the choice to invest in the non-aviation sector can be ascribed to the strategic orientation adopted by airport managers, rather than by the growth rates of passengers. The originality of the article is twofold. The first aspect is related to the methodology adopted that is innovative for this industry, the second concern the results obtained that contradict the apparently 'trivial' question of the relevance of NAR as the reported number of passengers increases.