You disturbed a large number of electrons when you posted

"Then why don't airports use weathervanes instead of windsocks? "

but we think you know weathervanes are telling us where the last wind
came from, and windsocks give us some information as to how hard it's
blowing at the moment.

Flags work well at doing that, too but come to think of it, I'd rather
have a windsock on the flagstick of my golfcourse than a flag.

(and several more on high poles about a 100 yards out, although that
would remove still another excuse for for bad golf shots.)