Can rail reduce British aviation emissions?

• We constructed OD data for the UK domestic and international aviation sector. • Data allows exploration of passenger flows and emissions from 1990 to 2021. • Aviation demand is compared to current and future rail network. • 41 % of passengers could switch to rail, accounting for 14 % of aviation emissions. • Minority of long-haul flights account for most aviation emissions. We analyse UK airport origin–destination data from 1990 to 2021 to understand the extent to which a modal shift to rail may reduce aviation emissions. We find that 41 % of UK aviation passengers travel on routes that can be done by rail in less than 24 h. However, these passengers account for only 14 % of UK aviation emissions because long-haul flights contribute the majority of emissions. Some popular destinations (e.g. Spanish Islands) are inaccessible by rail and may be suitable for destination switching. We also find rapid growth in flights to international hub airports used for connecting journeys. This has implications for carbon accounting, suggesting that a significant and growing proportion of UK residents’ aviation emissions are being excluded from national accounts. Finally, the paper recommends some interventions that might encourage a modal shift to rail.