Reason probably is that, at long distance, lower air resistance at height starts to count.
Also, it’s easier to move planes around than to move rail tracks around, so if a destination is popular for only a short time (say for the Olympic Games, or for the hajj (https://en.wikipedia.org/wiki/King_Abdulaziz_International_A...), it may be energetically cheaper to build and (basically) discard an airfield than to build and (basically) discard a long rail track.
>Reason probably is that, at long distance, lower air resistance at height starts to count.
This isn't as big a factor as you might think. While older aircraft were optimized for design/cruise altitude, modern jets are designed to account for the imposed altitude restrictions and speed limits of departure and approach. They also have a much wider/efficient operating envelope, and due to improved logistics, are dispatched, loaded, and operated more appropriately wrt to flight plan profiles.
Reason probably is that, at long distance, lower air resistance at height starts to count.
Also, it’s easier to move planes around than to move rail tracks around, so if a destination is popular for only a short time (say for the Olympic Games, or for the hajj (https://en.wikipedia.org/wiki/King_Abdulaziz_International_A...), it may be energetically cheaper to build and (basically) discard an airfield than to build and (basically) discard a long rail track.