In this paper, we provide a novel application of synthetic control methods by offering two major modifications to the existing methodological framework. We provide the first complete ex-post evaluation of the causal impact of carbon pricing on aviation supply, expressed in terms of airline output (i.e., number of seats supplied at the airline-route level). We investigated the policy change in the European Union Emission Trading System (EU ETS), the first large greenhouse gas emissions trading scheme in the world. We distinguish between low-cost, regional and full service airlines, short and medium/long-haul routes, routes towards (or from) hub airports versus non-hub airports, monopolistic versus non-monopolistic routes. The analysis shows that the EU ETS does not have a substantial impact on the average aircraft size, while it has caused a reduction of total airline seat capacity and flight frequency, with the percentage of airline seat capacity reduction reaching above 20% at its peak. The overall effect of the policy has a remarkable impact on low-cost and regional airlines, short-haul routes, spoke–spoke markets and monopolistic routes. Our results are the first empirical confirmation to the theoretical prediction in the aviation literature that emission charges will reduce flight frequency and increase load factors while having no effect on aircraft size.

在本文中，我们通过对现有方法框架进行两个主要修改来提供合成控制方法的新应用。我们首次对碳定价对航空供应的因果影响进行了完整的事后评估，以航空公司产出（即航空公司航线水平供应的座位数）表示。我们调查了世界上第一个大型温室气体排放交易计划——欧盟排放交易体系（EU ETS）的政策变化。我们区分低成本、区域性和全方位服务的航空公司、短途和中/长途航线、前往（或来自）枢纽机场与非枢纽机场的航线、垄断与非垄断航线。分析表明，EU ETS 对平均飞机尺寸没有实质性影响，同时也造成了航空公司总座位容量和航班频率的减少，航空公司座位容量减少的百分比在高峰时达到了20%以上。该政策的总体效果对低成本和支线航空公司、短途航线、辐条市场和垄断航线产生了显着影响。我们的结果是航空文献中理论预测的第一个实证证实，即排放费将减少飞行频率并增加载客率，同时对飞机尺寸没有影响。