Here's another great idea from a fellow Mom-Blogger; Amazing Mae
Road Trip Pillow Cases!
Seriously... How cute are these?! And practical, AND fun!!
Go to her blog for a complete tutorial on how to sew one from scratch.
You could also use an existing pillowcase (new ones at Walmart are only a couple dollars for a package of 2) and simply sew a pocket onto the front and a handle on the side.
These would be fun for sleepovers as well!