I am a big fan of hats. This kind of hat is one of my favorite. I have already sewed so many. It’s so easy to sew.
All you need is a 21,65″ long elastic (for example lycra) knit fabric and tread. If the fabric is stretchy enough you don’t have to use the whole head circumference. It means take the head circumference minus 1,57″-1,97″.
Have a nice autumn!