I have a few car seat blankets to make for my nephew. hes about 6 months now. I just take a fq and some minky type fabric and use that. they are great and i used them for my last baby whos 15 months now. i still have them in the car for her convertible car seat. I worry too much about her suffocating with a regular size quilt in the car. But i know many who use small blankets in the car because they are not supposed to use jackets with the seat belts. I have always wrapped my babys up with a blanket even when they are in a regular bed. I have three baby quilts that I use for my baby and have used them since she was born. its a personal preference.