Purpose: For strategic and competitive insights, the purpose of this paper is to measure and benchmark the comparative operating efficiencies of Association of Southeast Asian Nations’ (ASEAN) major airlines and present a new interpretation along with managerial implications. Design/methodology/approach: This research statistically tests returns to scale and the equality of mean efficiencies for 15 ASEAN airlines covering the period 2010-2014. The disaggregate input efficiency of ASEAN airlines is computed by comparing the target and actual inputs. Findings: The disaggregate input efficiency of ASEAN airlines shows that aircraft efficiency is the lowest, operating cost efficiency is better, and available seat efficiency is the best. Originality/value: This paper applies data envelopment analysis models, disaggregated input efficiency measures, and bootstrapping approaches to compute the operational efficiency of ASEAN airlines. Strategic suggestions are made to improve the operational efficiency of ASEAN airlines.