I tweaked it a bit and made the rectangle 19" long so the hat covers my ears with a 1" hem. Make sure the direction with the stretch goes around your head otherwise it won't work (so you'll need to buy at least a half yard of fleece, or a little more if you want it to cover your ears like mine). I didn't tack the cat ears because they seem to form naturally like the knitted versions.
My fleece is wide enough to get 4 hats out of 5/8 of a yard (or if you want to make your hats shorter, then you can get 4 hats out of a half yard.)
This fleece is from Joann's and is called "Anti Pill Fleece Fabric-Beetroot Tonal Tie Dye" on their website.
I sewed 8 hats last night out of 1.125 yards of this fleece in about 75 minutes assembly line style and that's with legit seam finishes on the serger, tucking serger thread tails, serging the raw edges and twin needle stitching the hem. Going to stitch up another 8 in hot pink, maybe more!