Last year I made my husband a similar hat (here). Hats are fun to make because they are a quick project. If my family has the need and want I decided they can have one new hat each year. When it came time for my 4 year old to pick a style of hat this year he requested one just like his Dad's. :)
I did make a few changes to be more suitable for a 4 year old. First I added earflaps to the hat. The hat is a simple single crochet with increases until I reach the size I want. I did not have a pattern for the earflaps, just figured it out on the fly.
He loves it!
One of these days my family is going to have to watch The Nightmare Before Christmas. I hope we like it!