Abstract Over the last years, the exponential growth of air traffic has led to an increase in aviation-related negative externalities, raising the issue of sustainable growth in air transport to the forefront of policymaker and national government debates. One of the strategies designed to reverse this trend is to enable modal shift toward greener transport modes where technically possible. Our research quantifies, at a pan-European level, the possible impact of a policy of cancellations of short-medium-haul air routes that are currently effectively served by alternative transport modes, and mainly by high-speed rail. Following recently introduced policy initiatives, we analyze route substitutability based on not only the increase in travel time faced by passengers due to the enforced modal shift, but also the corresponding change in their generalized travel costs. At a macro-European level, our analysis reveals that about 26.5 million (3.02% of intra-European) offered seats may be cancelled and substituted with alternative trips without any significant increase in travel time for passengers. The French domestic market and flag carrier Air France lead the standings both in terms of the number of substitutable offered seats and potential CO2 savings. Moreover, analyzing the impacts at the regional level, we outline that this policy would preserve disadvantaged regions by placing the burden of reducing emissions from aviation mainly on areas already efficiently served by alternative transport modes. Overall, the replacement of short-medium haul routes would undoubtedly mark a step toward meeting medium-long-term targets of greenhouse gas emission reduction. Eventually, we discussed a number of key issues that policymakers need to address for a successful and not-myopic implementation of the policy.

Highlights • The paper evaluates intra-European short-medium-haul air routes potentially subject to be substituted. • Route substitutability analyzed by higher travel time/generalized travel cost induced by modal shift. • Routes that might be substituted are mainly domestic. • Potential CO2 savings and replaceable offered seats are not equally distributed. • We raise a set of key issues that policymakers should consider for successful policy implementation.