The carbon footprint of academia has become a pressing concern and an emerging research area, with a particular focus on greenhouse gas emissions from research travels. Mitigation strategies often revolve around encouraging virtual communication and adopting more sustainable transportation modes over short distances. However, these approaches are rarely subjected to rigorous quantitative assessments or meaningful comparisons. This study analyzes a unique database of about 130,000 travel segments by car, train and plane in 159 research units across diverse disciplines and locations in France. We investigate the patterns and associated carbon footprint of these research travels and explore a diversity of mitigation options, including existing institutional guidelines. Our analysis shows that air travel overwhelmingly outweighs the carbon footprint of research travel, representing more than 96% of greenhouse gas (GHG) emissions. Intercontinental flights are infrequent (less than 10% of all plane trips) but dominate GHG travel emissions, accounting for over 64% of total emissions. In contrast, domestic and continental flights are the most common but their mitigation potential by modal shift to train is limited (e.g., less than 15% for trips under 1,000 km). Similar reductions can be achieved by targeting a small subset of travels, for example by modulating the frequency of conference attendance. The greatest mitigation potential lies in moderating air mileage, for instance by reducing the number of flights. Strategies focusing on electrification or modal shifts for cars are found to have negligible impact. In the absence of low-carbon alternatives for long-haul flights, we contend that only comprehensive strategies and policies aimed at moderating air travel distance or frequency can achieve a significant reduction in the GHG emissions from academic travel.