Résumé : This study addresses behavioural change in environmental management practices of European full-service airline groups. Building on the International Environmental Alignment Framework, it is assumed that the ongoing process of environmental institutionalization has forced European airlines over the last 20 years to gradually integrate environmental aspects into their organization and management, thus developing pro-active management practices. Special attention is paid to the distinction between an external and an internal dimension of environmental management practices. It is assumed that besides coercive, normative and mimetic pressures also reputation and top management commitment affect airline’s behaviour. For this purpose, a qualitative comparative case study analysis of two European airline Groups – SAS AB and Air France-KLM – was conducted for the time between 2000 and 2019. The data collection was based on an in-depth document review and three semi-structured interviews. While the results indicate a gradual integration of environmental aspects into airline’s organizational structures, they also show the persistence of profit-oriented behaviour patterns, that prevent a shift to ecological excellence. The findings suggest a link between the market structures of the international air transport industry and the barriers to the introduction of coercive instruments. However, this needs further empirical evidence before a general trend can be assumed. This study contributes to the research on corporate environmental management in the European airline industry. The complexity of the theoretical framework adds to the originality of the research.