Yes, it's always going to be unfeasible to cross the Atlantic or Pacific by train.
But the vast, vast majority of air journeys taken every day aren't trans-oceanic ones. Most journeys are between destinations within the Americas or within Eurasia and Africa. There are an awful lot of journeys by plane that could be moved to trains if the infrastructure was right.
Looks like a standard GTK4 app to me. Whether or not that is to someone's tastes is obviously subjective, but it uses the same design language as every other GTK app under the sun.
GTK apps always look out of place on Windows though. Looks far more sensible in its native environment (i.e. *nix running GNOME).