Authors’ response to Beuthe’s comment on “An aggregate demand model for air passenger traffic in the hub-and-spoke network”

In his comment on our paper, Beuthe identifies several results that he considers implausible and proposes some improvements to our model specification that would address these concerns. While his comment is tightly argued and rigorously formulated, much of it is based on a false premise about the nature of the relationship between hub capacity and its attractiveness to connecting passengers. Beuthe assumes that the effect arises from changes in “congestion” and in particular the ratio of passengers to capacity. In the development of the demand model in our paper, we do not claim that this is the mechanism at work, and we do not believe that it is. The comment does, however, point to a flaw in the paper, which is that we do not clearly explain the mechanisms by which hub capacity – as measured in our paper – may affect hub traffic. Our exposition of the concepts of “direct” and “indirect” benefit in that paper is confusing and not entirely correct. Let us try to rectify this.