Flight-level carbon efficiency of low-cost carriers: a China–U.S. Comparison

This study provides the first empirical evidence on flight‑level carbon efficiency of low‑cost carriers (LCCs) in China and the United States. Using 23,953,470 flight records linked to engine data, geospatial references, and load factors, we estimate CO₂ by landing–takeoff (LTO) segment and the climb–cruise–descent (CCD) segment and compute intensities per seat‑km and passenger‑km. Contrary to the common belief that advanced economies achieve superior efficiency, our findings reveal that Chinese LCCs consistently outperform U.S. in carbon efficiency. Spatially, China's gains concentrate along dense southeastern corridors, while U.S. coastal short‑haul remains carbon‑intensive. Aircraft heterogeneity and assignment also matter: the A320 family outperforms 737‑700/800, especially on medium/long-haul flights. Comparison with full-service carriers (FSCs) confirms the superior carbon efficiency of LCCs. However, as LCCs have less room for further carbon reductions, mitigation policies focused on activity growth risk penalizing them. This highlights the need for intensity-based and equitable regulatory frameworks.