This chapter traces the historical development of the air transport industry from its pioneering days to the present. It identifies four key periods: the early years of regulated monopoly, the era of liberalization, the rise of low-cost carriers, and the current phase characterized by hybridization. Each period is examined through the lens of business models, competition, and regulatory changes. The chapter demonstrates how liberalization in the United States and then Europe deeply transformed airline strategies, market structures, and consumer behaviors. It also underlines how innovation and cost pressure led to the emergence of low-cost carriers, who profoundly reshaped industry norms. Finally, it discusses the recent hybridization of business models since the Covid-19 crisis. This historical lens helps readers grasp the current dynamics and tensions of the industry.