And that is the 64 dollar question.

Huge walls aka “mountain ranges”.

I've wondered if you could do something like that at airports that have problems with crosswinds. Could you build tall walls on both sides of the runway to block crosswinds?

I'd expect there would be turbulence around the entrance to the walled area which might be dangerous, but that could probably be addressed be having the walls flair out near and beyond the end of the runway, and also past the end have the height ramp down to 0 instead of just stopping abruptly.

I fly out of an airport that used to have a lot of trees along one side of the runway. It had both of the effects you mention, of moderating the wind but also causing turbulence. The problem isn’t just the ends, but also the top, as the wind curls over. Overall I think the benefit is fairly small, and you’re a lot better off building perpendicular runways if you can.

They do that (for ships) in the Netherlands but extending it to planes seems impractical

https://en.wikipedia.org/wiki/Rozenburg_wind_wall:

”Rozenburg wind wall in Rozenburg, Netherlands, is a wall built to block wind from entering the Calandkanaal, and ease the passage of large cargo ships through the narrow canal, particularly through the Calandbrug bridge. The wall blocks about 75% of the wind and allows the ships to pass smoothly. The wall is 1600 meters long and it is made up of 125 rectangular and cylindrical slabs, each about 25 meters tall and 18 meters wide.”

Edit: beter photos at http://googlesightseeing.com/2013/05/rozenburg-wind-wall/. That page points to a dutch-language video that shows hoe tight that passage is: https://youtu.be/H4ZIMXjMRJk?t=3m5s