This paper investigates the potential pathways and associated requirements to meet a goal of net-zero greenhouse gas (GHG) emissions from the US commercial aviation sector by 2050 as outlined in the US 2021 Aviation Climate Action Plan. Aviation traffic (RTK) is projected to grow at an average of 2.0% per annum between 2019 and 2050, suggesting that a progressive and ultimately total decoupling of emissions from traffic growth will be required to meet the US aviation sector goal. Aircraft technology advancements, operational efficiency improvements, sustainable aviation fuels, and market-based measures (MBM) are considered as emissions reductions measures towards the goal. A parametric analysis framework is used to develop low, medium, and high emission reduction scenarios for each of these emissions reduction measures. If aircraft technology, operations, and fuels were frozen at 2019 levels, the aviation sector is projected to emit ≈430 million tonnes of CO₂ (MtCO₂) in 2050. Retirements of older aircraft, replaced by current-generation alternatives, may contribute 17% of the total 2050 emissions reduction goal. Further introduction of advanced aircraft technologies may contribute an additional system-level 11% emissions reductions towards the goal. Operational improvements may contribute ≈2% with a range from 1.5 to 4%. The remaining 70% of emissions in 2050 will be addressed through a combination of sustainable fuels and MBM, where appropriate. The level of contribution from fuels will be dependent on continued production ramp-up to meet aviation demand as well as improvements in lifecycle emissions reduction factor (ERF) for current and future fuel feedstock and production pathways, ranging from 0% for current petroleum-based fuels to 100% for sustainable aviation fuels with zero life-cycle emissions. Meeting a net-zero emissions goal by 2050 with SAF would require an increase in SAF production by 57% annually from 2022 to 2030 and 13% per year thereafter, reaching 100% emissions reductions factor by 2050. MBM may fill the gap between residual lifecycle emissions after accounting for all other in-sector improvement opportunities and the goal.

本文研究了美国 2021 年航空气候行动计划中概述的到 2050 年实现美国商业航空业温室气体 (GHG) 净零排放目标的潜在途径和相关要求。预计 2019 年至 2050 年间，航空运输量 (RTK) 将以平均每年 2.0% 的速度增长，这表明需要逐步并最终完全将排放量与运输量增长脱钩，才能实现美国航空业的目标。飞机技术进步、运营效率提高、可持续航空燃料和基于市场的措施（MBM）被视为实现该目标的减排措施。参数分析框架用于为每项减排措施制定低、中、高减排情景。如果飞机技术，₂（百万吨CO ₂）到 2050 年。旧飞机的退役并被当前一代替代品取代，可能会贡献 2050 年总减排目标的 17%。进一步引入先进飞机技术可能会为实现这一目标额外贡献系统级11%的减排量。运营改进可能贡献约 2%，范围为 1.5% 至 4%。到 2050 年，剩余 70% 的排放量将酌情通过可持续燃料和 MBM 的结合来解决。燃料的贡献水平将取决于满足航空需求的持续产量增长以及当前和未来燃料原料和生产途径的生命周期减排系数（ERF）的改善，范围从当前石油基的 0％ 100%使用可持续航空燃料，生命周期零排放。