Long-distance mobility sustainability, high-speed railways (HSR) decarbonization effect, and bans for short-haul flights are debated in Europe. Yet, holistic environmental assessments on these topics are scarce. A comparative life cycle assessment (LCA) was conducted on the Paris-Bordeaux transportation options in France: HSR, plane, coach, personal car, and carpooling. The overall ranking on four environmental indicators, from best to worst, is as follows: coach, HSR, carpooling, private car, and plane. Scenario analyses showed that increasing train occupancy decreases the environmental impact of the mode (-12%), while decreasing speed does not. Moreover, worldwide carbon footprints of electric HSR modes range 30-120 gCO2eq per passenger-kilometer traveled. Finally, a consequential LCA highlighted carbon paybacks of the HSR project. Under a business-as-usual trip substitution scenario, the HSR gets net-zero 60 years after construction. With a short-haul flight ban, it occurs after 10 years. This advocates for generalizing short-haul flight bans and investing in HSR infrastructure.