I love both my original and 2nd generation BlackRock Down Hats, but I stopped wearing them in windy weather because the wind would just fill up the inside of the hat and it would not keep me warm, but I found a fix.
See in the photos how I put 2 layers of 1/4 flat elastic on to pull the beanie tight on my head and ears. The elastic is a double but I cut them at 5 inches (which when stretched after being doubled to almost 5 inches), figured by trial and error where to put the first sice and stitched in in, then stretched it to where I wanted it to be on the other side and stitched that side. I like it on the first so I did the second too.
Then I cut a piece of lightweight fabric 1 1/8 wide by 5 1/8 long for each hat and stitched one end then the other then while holding the hat with the double band of elastic taught, I stitched the sides enclosing the elastic. I used the fabric from a Frog Togs bag. The elastic now puckered the hat nicely and when I put it on it is wind proof and also feels better on my head. I was always wondering if it were down on my head all the way, now I know it is.