© 2021 Elsevier LtdOur paper determines the best competitive strategy that can be implemented by existing and potential air cargo carriers in the Turkish Air Cargo Industry with the operationalization of Istanbul Airport (IGA) and reveals the competitiveness level of the industry for four bases. We look at the competitiveness levels by analyzing the competitive environment of the industry nationally and internationally both before and post IGA (estimated). We use fuzzy TOPSIS (FTOPSIS) based on the Fuzzy AHP (FAHP) to handle vagueness, which is inherent in the nature of new competition conditions integrating the framework of Porter's five forces analysis. In our study, we use the five forces as our main criteria (with a total of 19 sub-criteria) and the competitive strategies as our alternatives. Our results reveal that the cost-focused strategy is the best competitive strategy that can be implemented by existing and potential carriers in the industry. Another significant result underscores the fact that IGA increases the competitiveness level of the Turkish Air Cargo Industry both nationally and internationally to a fairly high level. Also, the threat of potential competitors is first among the five forces in the industry's new conditions. Our study fills the gap in the literature on the effects of major structural changes in an air cargo industry on the competition among carriers.