航空服务协议、连通性与排放

No2026-04 – March Air Service Agreements,Connectivity and Emissions Lionel Fontagné, Cristina Mitaritonna, Gianluca Orefice& Gianluca Santoni Highlights The signature of Air Service Agreements (ASAs) allows airlines to reshape the international route network ina more efficient way and ultimately reduce CO2 emissions per passenger. Using unique data on airline tickets and ASAs in force during the period 2012-2019, we show that the re-organization of international flight routes induced by ASAs reduces CO2 emissions per worker by 3.9%. The counterfactual analysis suggests that a further liberalization of the air services, in which all country pairswould be linked full liberalization ASAs, would imply a 2.3% reduction in emissions per passenger. Abstract The average energy efficiency of the aviation sector has increased by 2.7 percent per year since 2012, fallingshort of the 6 percent increase in demand. Optimizing routes by reducing the number of legs per flight is oneway to complement technological advances in aircraft and fuels to reduce aviation's environmental footprint. Thesignature of Air Service Agreements (ASAs) allows airlines to reorganize their flight routes. They reshape theinternational route network in a more efficient way and ultimately reduce CO2 emissions per passenger. On theother hand, ASAs increase the demand for international flights, which may offset the reduction in overall CO2 Keywords Air Service Agreements, Air Transportation, Environment. JEL F13, L93, F64. Working Paper 1.Introduction The provision of air services has been shown to affect the economic landscape, facilitate thedevelopment of interconnected geographic areas, and encourage face-to-face relationships that support business relationships, international trade, and even technology transfer (Bahar et al.,2023; Blonigen and Cristea, 2015; Campante and Yanagizawa-Drott, 2018; Cristea, 2011; Hovhannisyan and Keller, 2015; Söderlund, 2023). Hence, reducing frictions that hinder thesupply of international air services can be beneficial for countries. At the same time, similar to the case of international trade, the environmental impact of air traffic can be divided intotechnical, scale, and composition effects (Copeland and Taylor, 1993; Grossman and Krueger,1993; Shapiro, 2025). Air traffic liberalizationviaAir Service Agreements (ASAs hereafter) isexpected to have: (i) atechnical effect(more efficient routes, fewer take-offs and landings as In this paper, we tackle this question and show how ASAs, by promoting direct flights, shapethe carbon emissions footprint of air travel. To do so, we combine granular data on passengertickets from 2012 to 2019, flight routes, the number of legs, and airport locations with ex-haustive information on Air Service Agreements and a detailed simulator of aircraft emissions.Our econometric approach relies on both difference-in-differences techniques and the eventstudy approach to test the parallel trend assumption. By controlling for any country-year andcountry-pair factors affecting bilateral air services, as well as for any airline-specific technolog-ical and productivity shocks, we can claimcausalityin the impact of ASAs on internationalflight distance, legs, and, hence, emissions per passenger.The reduced-form econometric The reduced-form econometric analysis points to some clear-cut results: signing an ASA re-duces the distance between origin and destination by 1.6 percent, the number of legs by 3percent, and the emissions per passenger by 2.8 percent. However, the content of ASAs mat-ters: signing a fully liberalizing ASA reduces emissions per passenger by 5-6 percent, whilesigning a not-fully liberalizing ASA has no statistically significant impact on emissions per pas-senger. The counterfactual analysis suggests that the impact of the existing network of ASAsis a 1.9 percent reduction in emissions per passenger, resulting from a 2.8 percent increase in the number of passenger and a 0.9 percent increase in total CO2emissions.However, afurther liberalization of air services, in which all country pairs would be linked by ambitious (full liberalization) ASAs, would deliver another 2.3 percent reduction in emissions per pas- senger, a 4 percent increase in demand for more comfortable flights,1and a net 1.7 percent increase in emissions. The main message of the counterfactual analysis is that the scale effectsystematically overcomes the technical effect. On the other hand, passenger welfare increases. This paper builds on three strands of literature. First, discrimination in access to internationalair services has been shown to be a major obstacle to passenger traffic (Piermartini andRousová, 2013).The lack of ambition among several ASAs and their network complexityreduce the economic performance of air companies, hinder competition, and eventually increase transportation costs. Open skies agreements and consolidated agreements inspired by thosesigned by the EU would in