My personal favorite is the Snoopy on the top left, which one is your favorite? ;-)
So we started off with flooding the cookies with a white base icing and let it dry. When the base icing is dry use an edible pen or marker to draw the characters on top of the white icing. These will act as a guide as you decorate your cookies - see the picture below.
For me its hard to get an even distribution of airbrush colours all around the cookies. Just a side note from my learning experience of using the airbrush, use it in a good light. Don't be like me and start using it at night when you can't even see the colours spraying out! lol >.<
We mixed 1/3 orange & 2/3 yellow airbrush colours and put it into the airbrush cup. Spray all around the cookies and be sure to start off with light spray as you can layer it up to build the colour.
Lets start with the simplest one - Charlie Brown cookie.
Start with using skin colour icing for his head area, wait for a few minutes until it dries a bit and add his ear, neck and arm - see picture below. Then fill in the rest of his yellow top and the black chevron in the middle of his top. Lastly add his nose and draw his face with edible markers.