Howdy and Welcome to CF!
One should not expect all answers on a forum to be serious or on topic.
It seems to me that the wind sock for an airport
should be durable, dependable, and highly visible
My caution: Do not pick a material that will get brittle and fray after long sun exposure.
The other weak point will be the stitching, so pick UV resistant thread
(the sail making thread mentioned earlier).
And, make sure the sock is long enough and will hang properly once put on the post.
How it is shaped, length and how it is eventually mounted is important.
While the following sock may get noticed
it may also cause a pilot distraction.