The air transport industry has numerous social, cultural and economic benefits. The sector plays a major role in the economic and social development of countries, cities and regions. The air transport industry enables increased interaction among cultures. It speeds up access to long distances and guarantees that aid is quickly and safely delivered to areas in natural disasters. In the twenty-first century, where technological changes and transformations are increasing, there are also significant changes in the air transport industry. In addition, with the globalization, the importance of the air transport industry is increasing. Especially after the 1970s, many deregulations were made for the liberalization of the air transport sector. In this way, the air transport industry has become a global sector. Many airlines were established. In addition, competition among airlines has increased significantly. In this process, airlines with sustainable financial indicators gained competitive advantage. In other words, airlines with sustainable cash flow, debt structure and profitability created more value for their stakeholders. In this study, we focus on airlines with sustainable financial performance. The air transport industry is a capital-intensive sector with a very low margin. Demand for airline changes seasonally. In other words, demand is quite high in summer and very low in winter. In addition, the air transport industry is highly sensitive to incidents, wars and outbreaks occurring spherically. For example, the 2001 terrorist attack and the 2008–2009 global financial crisis have caused the sector to experience financial difficulties. Finally, the COVID-19 pandemic, which began towards the end of 2019 and still continues, has also significantly affected the industry. In such situations and processes, airlines with sustainable financial indicators can take the lead in the competition. Therefore, it is important to analyse the financial statements of airlines in the last 10 years. In the first stage of this study, we have reached the last 10 years of financial data of top 20 airlines operating globally. In the second stage, we determined variables to measure the sustainable financial performance of airlines. We used the studies in the literature for the determination of the variables. Within the scope of the study, we created four different models in order to reveal the financial performance of airlines. We used the data envelope analysis method to compare the financial performance of airlines. Using this analysis, we will determine which airlines are efficient during the period under review. In this way, we will reveal which airline has a sustainable financial performance. We aim to compare the results obtained in the study with the studies in the literature. In addition, the aim of this study is to fill the gap in the literature.
