This study identifies strategic directions to realize sustainability in airline in-flight meal services as Environmental, Social, and Governance (ESG) management becomes integral to aviation. Using literature review and comparative case analysis, we examine domestic carriers (Korean Air, Asiana Airlines, Jeju Air) and international airlines (Singapore Airlines, Finnair, ANA, KLM). Domestic airlines primarily emphasize visible initiatives local ingredient sourcing, eco-friendly packaging, and portion optimization yet these efforts are often fragmented and activity-based. In contrast, international carriers operate performance-oriented systems that integrate circular food processes, digital waste/carbon tracking, supplier engagement, and externally audited reporting aligned with global standards. Across cases, three factors consistently differentiate sustainability maturity: data transparency (quantitative indicators and verification), governance accountability (dedicated ESG structures and audits), and stakeholder participation (passenger co-creation via pre-order programs and campaigns). Based on these findings, four development directions are proposed for Korean airlines: (1) build regional, low-carbon supply chains; (2) implement low-carbon cooking and waste-minimizing production; (3) expand participatory eco-campaigns (e.g., pre-order, donation, recycling); and (4) standardize evaluation and disclosure in line with GRI/CSRD and aviation guidelines. Positioning in-flight meals as strategic ESG assets can strengthen brand equity and competitiveness while advancing environmental stewardship in aviation foodservice.