From this BBC article: https://www.bbc.com/news/science-environment-49349566
“Train travel virtually always comes out better than plane, often by a lot. A journey from London to Madrid would emit 43kg of CO2 per passenger by train, but 118kg by plane (or 265kg if the non-CO2 emissions are included), according to EcoPassenger.” That’s almost 3 times as much CO2 per passenger mile, even more if you consider the extra impact that plane emissions have. (Read the article.)
The difference is even more dramatic for short-haul trips, which is what all of the flights that will be canceled are.
Every government in the world imposes regulations that it deems to be in the public interest. Not all of them work, but it seems to me this one is worth trying and analyzing.