Airline customer service, a vital part in successful organizations, plays an important role in improving company profits. Since there are few studies considering customer service in Iranian airlines, this paper employs Delta model, which is a customer-based approach in strategic management, to improve aircraft maintenance and customer satisfaction. In this research, six service levels are defined and data is collected by interviews. The aim of this research is to identify business strategic opportunities to improve customer service. The main contribution of this paper is to employ Delta model in the Iranian airline industry. The results shows that it can be possible to improve airline customer service using Delta model. The main conclusion to be drawn from the results is that scheduling and budgeting are the vital part in the airline customer service and working on can be a future research.