Air travel is a better natural competitor than highways. Ultimately highways are already sunk costs which can be seamlessly upgraded to work with new tech (ie m

Air travel is a better natural competitor than highways. Ultimately highways are already sunk costs which can be seamlessly upgraded to work with new tech (ie more efficient, and soon electric, cars). Air travel is heavily taxed rather than subsidised, and yet it's still preferable to road travel over long distances, for the simple reason that it's faster.