The lean green approach (LG) has gained importance in the service sector. LG is a recent approach that combines green management and lean thinking principles into a single paradigm. The simultaneous implementation of LG can help airlines improve resource efficiency, reduce costs, conserve the environment, and remain competitive. Although LG approach achieves many benefits for airlines, several challenges remain. The overall objective of this research is to explore the practices, opportunities, and challenges of the LG approach at airlines in Egypt. Moreover, this study also evaluates the effect of LG adoption on the airlines' competitive advantage (CA). Based upon the mixed methodology, this study conducted (18) semi-structured interviews with experts in airline companies operating in Egypt. Besides, a structured questionnaire was distributed to (89) participants to examine the effect of LG implementation on the CA of airlines. The empirical findings indicate that LG practices have a positive impact on the airlines' CA. The findings of interviews reveal that LG practices provide broad opportunities for airlines by enhancing the following issues: management of catering inventory, cost reduction, ground handling services, ecological behaviour for customers and employees, workflows and operational performance, aircraft maintenance, fuel consumption and recycling, and sustainability. The findings also illustrate a range of challenges that airlines may face when implementing LG practices, like keeping pace with technological development, human resource training policies, resistance to change, the culture of management, waste management, and sustainable aviation fuels. Finally, implications for practice as well as future research are discussed.