Air transportation in Brazil has been recently liberalized and one of the consequences of this process is
the concentration of flights in a few hubs. During the years 2006–2007 two fatal accidents created
unprecedented chaos in both land and air sides of the system with harmful consequences to tourism in
Brazil. The consequences were more airport congestion and many episodes of flight delays and cancellations
that lasted for several months. We argue that, among other factors, this state of blackout was
a result of the increase in the degree of concentration in few airports, particularly Congonhas (in Sa˜o
Paulo) and Brası´lia. Using data obtained from a survey with Brazilian experts, a comparison was made
with two existing methods (the one used by the US Federal Aviation Administration and the usual
Herfindahl–Hirschman method) in order to calculate the number of hubs in Brazil. Due to the huge
discrepancy obtained between data from the survey and the other two methods considered, a new
mathematical method based on the Herfindahl–Hirschman Index was proposed to identify the number
of hubs in a given network. Drawing from the examples of what happened to tourist destinations during
and after the air transport crisis in Brazil, the article concludes discussing the need for a more accurate
tool to identify and to monitor the concentration of flights at the Brazilian air transportation network and
its importance to tourism