This paper analyses the spatial distribution of seat capacity in the EU from 1990 to 2009 and sheds light on the contrasting results in the literature. It contributes to the debate on the deregulation and whether the rise of hub-and-spoke networks and the success of low-cost carriers lead to concentration or deconcentration. We use the Gini index and its decomposition to evaluate the contribution of airport subgroups and airline networks to the overall concentration of seat capacity. We conclude that, overall, seat capacity follows a spatial deconcentration pattern. While intra-EU seat capacity became more spatially deconcentrated, extra-EU seat capacity concentrated. However, our results do not support the general view that network carriers tend to increase concentration levels and low-cost carriers to decrease them, leading us to a reinterpretation of the impacts of air transport deregulation. The results show the increasing importance of foreign carriers and new strategies such as hub-bypassing.