The objective of this research is to identify the current practices required for lean implementation in order to develop a good framework for understanding relationships between current practices and service quality outcome resulted from lean implementation in airlines industry in Thailand. The questionnaire survey was employed for empirically collecting data. In total, 600 questionnaires were distributed to employees involved as part of lean implementation in four leading airlines in Thailand. In total, 400 questionnaires were completed, considering as 66.67 percent response rate. Correlation analysis and multiple regression analysis were conducted to understand the relationship between these current practices and lean implementation outcome related to service quality. The findings indicated significant relationships of all factors toward the overall service quality resulted from lean adoption. As a result, this study highlights the importance of employee engagement, planning and control and customer relations as three main factors affecting service quality improvement under lean implementation. Further, the findings from multiple linear regression analysis suggested that there are four elements of lean operations those can be used to explain the overall service quality of airlines companies, which are top management and leadership, planning and control, supplier relations, and employee engagement. The results will also provide practitioners with guidelines in implementing lean more effectively for enhancing service quality of airlines companies.