true point: planes should be used only for intercontinental travel: for exemple dedicate 2-3 airport hubs in all europe, and the rest of it should only be accessed by train. look up european sky on flightradar: it is always rush hour up there, and probably not so many intercontinental flights. Air travel should also be limited cross country only in Asia’s case: and the number of flight hubs should be reduced to a minimum and leave the rest of the country to be accessed through train