Abstract: To address the contradiction between the rapid growth of China's civil aviation and deep decarbonization, the single path of sustainable aviation fuel (SAF) is confronted with the predicament of technical ceiling and offset by demand growth. This study constructs the FLEET model integrating mixed integer programming (MIP) and system dynamics (SD), establishes a two-way feedback mechanism of "micro-operation-macro-policy", and quantifies the synergistic emission reduction effect of multiple paths (SAF, new technology aircraft, and operation optimization). The core findings include: (1) Potential and limitations of SAF: When the SAF blending ratio is in the range of 0~30%, every 10% increase can reduce emissions by 12.7%; after exceeding 30%, the marginal benefit decreases significantly, which is restricted by raw material gap and PIL technical bottlenecks. (2) Necessity of multi-path synergy: under the mandatory blending scenario (SAF 50% + GDP annual growth rate 5.5%), carbon emissions in 2050 would still increase by 73% compared with 2019, and the increase is affected by the fluctuations in transport volume (±0.5%) and the actual blending efficiency of SAF (±5%). The optimal combination scenario (SAF 65% + new technology aircraft 40% + operation optimization 30% + market mechanism 15%) can achieve a 49.19% emission reduction in 2050. The emission reduction per unit policy incentive is 2.3 times of the single SAF path, forming technical complementarity, cost synergy, and emission reduction multiplier effect. (3) Carbon quota price threshold and heterogeneity: The carbon quota price exceeding 200 yuan per ton is the key threshold to trigger the technological leap of airlines; there are subject and regional heterogeneities in response (the emission reduction efficiency of eastern hubs is 1.35 tons per 10000 yuan larger than 0.87 tons per 10000 yuan of western branches). It is revealed that China's civil aviation emission reduction needs to break through the dependence on a single technology, and a three-stage "technology-raw material-policy" synergy roadmap is proposed (2025-2035 HEFA scale; 2035-2045 raw material diversification; 2045-2050 policy deepening), which provides a quantitative basis for phased policy design and engineering application.

Key words: air transportation, carbon emission reduction potential, FLEET model, sustainable aviation fuel, China Civil Aviation

摘要： 针对中国民航高速增长与深度脱碳的矛盾，单一可持续航空燃料(SAF)路径面临技术天花板与需求增长抵消困境。构建融合混合整数规划(MIP)与系统动力学(SD)的FLEET(Flight Legs per Equivalent aircraft Turnover)模型，建立“微观运营-宏观政策”双向反馈机制，量化多路径(SAF、新技术飞机及运营优化)协同减排效应。研究发现：SAF掺混比例在0~30%区间，每提升10%可减排12.7%；超30%后，边际效益显著递减，受原料缺口和PtL(Power-to-Liquid)技术瓶颈制约。强制掺混情景（SAF为50%+GDP年增速5.5%）下，2050年，碳排放较2019年仍增73%，其增幅受运输量波动(±0.5%)和SAF实际掺混效率(±5%)影响；最优组合情景（SAF为65%+新技术飞机40%+运营优化30%+市场机制15%）可实现2050年减排49.19%，单位政策激励减排量是单一SAF路径的2.3倍，形成技术互补、成本协同、减排乘数效应，证明了多路径协同的必要性。碳配额价格突破200元·t^-1是触发航司技术跃迁的关键阈值，响应存在主体与区域异质性（东部枢纽减排效率1.35t·万元^-1大于西部支线0.87t·万元^-1）。本文揭示了中国民航减排需突破单一技术依赖，提出“技术-原料-政策”三阶段协同路线图（2025—2035年HEFA(Hydroprocessed Esters and Fatty Acids)规模化；2035—2045年原料多元化；2045—2050年政策深化），为分阶段政策设计和工程应用提供量化依据。

关键词: 航空运输, 碳减排潜力, FLEET模型, 可持续航空燃料, 中国民航