The Brazilian airlines industry went through great changes since its deregulation at the beginning of this century. The appearance of Gol Linhas Aéreas Inteligentes, the first low-cost, low-fare, mass Internet ticket vendor airline in Latin America made passenger competition fiercer. The country's airline crisis, with its delayed and cancelled flights, the duopoly created by Gol's purchase of Varig, and the global financial crisis wrought havoc in the market. This study searches to identify these circumstances and within Data Envelopment Analysis (DEA) concepts, which are the fundamental cost/benefit more efficient flights from the passenger viewpoint. This study also shows why these flights are efficient within the sample.