The events of September 11,2001 followed by the oil price hike and the economic crisis of 2008, have lead to a drop in the demand for air travel. Airlines have attempted to return to profitability by cutting service in certain unattractive routes and airports. Simultaneously, delays and excess demand at a few major hubs have lead to airline introducing service at reliever airports. This dissertation attempts to capture the changes in the airline network by utilizing a supply-demand framework. / Ph. D.

[pt] Esse estudo investiga em que medida o desenvolvimento e introdução de novas aeronaves moldam a estrutura da rede das companhias aéreas. Argumento que aeronaves modernas são mais eficientes e adequadas para operar voos entre cidades menores e menos centrais, favorecendo assim o serviço em mais mercados na periferia da rede. Com dados sobre o tráfego aéreo dos Estados Unidos, utilizo um arcabouço de escolha discreta para modelar as decisões de entrada das companhias e a subsequente escolha de aeronave em cada mercado. Experimentos contrafactuais mostram que, caso o desenvolvimento de tecnologia tivesse cessado em 1999, a rede de tráfego aéreo como um todo estaria mais centralizada, a maioria das companhias estariam operando redes mais centradas em torno de hubs, alcançando menos cidades e servindo menos mercados. / [en] This paper studies to what extent the development of new aircraft shapes airlines network structure. I argue that modern aircraft are more efficient and well suited to operate flights between smaller and less central cities, hence favoring the service of more markets in the periphery of the network. Using U.S. air traffic data, I employ a discrete choice framework to model airlines entry decisions and the subsequent aircraft choice to each market. Counterfactual experiments show that had aircraft technology ceased to improve in 1999, the air traffic network as a whole would be more centralized, airlines would be operating more hub-centered networks, reaching fewer cities, and serving fewer markets.