Lining a Knit or Crochet Hat
Use Polar Fleece, t-shirt knit, up-cycle old sweaters and sweatshirts–you could even use a $1 Store hat!
When I first started crocheting and knitting hats I played around with different ideas for earflaps. Crochet ear flaps I learned were best in single crochet. On my knit earflap hats it was not uncommon for me to knit a second set of triangular ear-flaps and sew them into the hat. Unfortunately with the knits this method made them stick out a bit more than I preferred and even the tightest single crochet was no competition for the wind here near Lake Michigan.
Double knitting was an option but not one I was too enthused about so I let Google take me around the internet and ended up finding a great tutorial from the Uncommon Grace blog showing step by step how to sew a fabric lining into a hand knit hat. I have noticed since revisiting the site to post the link that the pics are not working but her instructions are very clear.