Air Transportation Planning 2

Referring to a book, Airline Network Development in Europe and it's implications for airport planning by Guillaume Burghowt, I would

like to share my studies from chapter 3 of the book, relating to spatial configuration of airline networks in Europe.

Here it is explained how the spatial concentration on an airline network configuration is studied, primarily with the use of the Gini configuration.

One of the earliest academic studies to consider the spatial structure of the US hub and spoke is by Ghobrial 1983.

Gini Coefficient is the most appropriate concentration measure for airline networks (Reynold-Feighan, 2001). The equation can be expressed as follows:

G= 1/2(x^2)(y) EiEj|yi-yj|

y=total no. of suplied seats per week at airport i or j

n= no. of airports in the airline network

The Gini coefficient is useful in measuring inequality of dispersion, with 0 being the value representing total equality, it is also known as the Gini Index.

The lorenz curve can help illustrate the Gini Index, the 45 degree line represents the case where all traffic is equally distributed

over all nodes in network, and Gini index has a value of 0. The greater the Gini Index the larger the area.

The max Gini Index increase with the nuber of airports in an airline's network:

Gmax=1-2/n , the max Gini Index can be observed in a single hib network where traffic flows are concentrated on one route.

Level of network concentration, N:

N= G/Gmax

An N of 1 means single radial network where traffic flows are concentrated just on one route. Decline in N would mean more even spread of seat capacity over airport population. The book then goes on to show the different network concentration level of European airlines.