Some believe that the Good People travel within a 'Fairy Wind' to move from one place to another, this is why must never interfere with a Fairy Wind. Indeed, some go so far as to tip their hat and say "God Bless Them" as they pass...
"One day I was going over the fields near Killeen, and it the quietest day of summer you ever saw. And all of a sudden I heard a great noise like thunder, and a blast of wind passed by me that laid the thistles low, and then all was quiet again. It might be that they were changing, for they change from place to place."
From duchas.ie
Art by Stephanie Law