Fewer seats, resilient frequencies: Impacts of large-scale High-Speed Rail liberalisation on air transport supply

Abstract

This paper examines the liberalisation of high-speed rail (HSR) as a driver of intermodal competition in long-distance passenger transport. While previous research has primarily focused on the effects of HSR infrastructure deployment on aviation, less is known about how opening HSR markets to new entrants reshapes this competition. Drawing on the Spanish HSR liberalisation in 2021, we are the first to evaluate the causal effects of a large-scale liberalisation on competing air transport supply. Using a regression discontinuity design, we find significant long-term reductions in airline seat supply (10- 16%), but limited impact on frequencies. We then uncover two mechanisms underlying these results. First, airlines’ primary response was to down-gauge aircraft. Second, a market share emerged from the need of legacy carriers to preserve frequencies to feed their hub. Our results underscore the broad and significant implications of liberalisation for intermodal substitution.