This study has been conducted out of an interest in the purpose of a company and its definition. The purpose of a company has been used in research for a long time, but there have been mixed perceptions of its definition and meaning. The effects of a company 's intent on its operations and the legitimacy of its operations have been challenging to demonstrate due to the subjectivity of the purpose and the lack of comparative information, but it is considered to be linked to financial success and the life cycle of the enterprise. This study examines the purpose of a company and the legitimacy it builds from the perspective of airlines. There has been previous research on the impact, ethics and communication of airline operations, but less attention has been paid to how airlines present their purpose in society and how to create a generally accepted or legitimate image of that purpose. In this study, attention is drawn to the purpose communicated by airlines and its basis for legitimacy. The study examines both the formation of purpose and the building of legitimacy on the basis of airline texts. The purpose of the company is determined using previous research. The theoretical background of the research is institutional theory, through which the concept of legitimacy is also defined. The most important theoretical models for the research are legitimacy strategies that describe the construction of legitimacy. In this study, with purpose and legitimacy, attention is also paid to business ethics and its implications for purpose and legitimacy. The research is qualitative, interpretive and critical. The method used in the study is critical content analysis, through which the purpose of the airline company has been sought to be perceived. Through content analysis, it has been possible to study society's self-evident, power relations and social expectations of companies. The research questions aim to create a picture of the purpose of the airline company and to identify the legitimacy strategies used to support it. The purpose and legitimacy of the airlines under investigation will be examined on the basis of the textual content of their own websites. The study identified four upper categories of content analysis on which airlines built their purpose. These are the airline's identification and differentiation from competitors, flying as part of the infrastructure, the airline as a responsible operator internally, and the airline's strategy and sustainability measures. Airlines were found to use the most legitimation strategies for rationalization and moralization, but legitimation strategies for authorization, narratification, and normalization were also identified from the material. In addition to this, the study identified sub-strategies of legitimation strategies that were specific to airlines. The results of the study provide new insights into the formation of a company’s purpose and strategies that seek to justify that purpose in society. In the future, this research topic could be deepened, for example, by conducting research on companies in different industries and also taking into account the company's stakeholders when assessing its legitimacy. Further research could also be done on whether the purpose communicated by companies corresponds to reality and how it is reflected in practice.