Bernardo, ValeriaFageda, Xavier, 1975-2026-01-192026-01-192025-10-011361-9209https://hdl.handle.net/2445/225754We examine the impact of new aircraft on total CO₂ emissions, seeking to determine whether their greater fuel efficiency may be offset by supply growth. We draw on granular global data at the aircraft–airline–route level between 2017 and 2023 and employ propensity score matching and entropy balancing to build a sample of comparable airline–route pairs operated or otherwise by new aircraft. We then analyze how the share of new aircraft correlates with supply and carbon emissions by estimating a high-dimensional fixed effects model. Overall, we find that the adoption of new aircraft has led to a substantial increase in supply that does, in part, offset the greater fuel efficiency. However, we find evidence of heterogeneous effects depending on the type of route or geographical area analyzed. All in all, our results point to the limitations of new aircraft for reducing carbon emissions at the global level.21 p.application/pdfengcc-by-nc-nd (c) Bernardo, Valeria ; Fageda, Xavier, 1975-, 2025http://creativecommons.org/licenses/by-nc-nd/4.0/AvionsContaminacióCarboniAirplanesPollutionCarboninfo:eu-repo/semantics/article7618932026-01-19info:eu-repo/semantics/openAccess