Top: Cassius Clay. I drew this from memory after watching all his fights back to back during his 65th birthday.... yes, I'm a big Muhammad Ali fan.
Bottom: Napoleon Dynamite with diffrent shirts. I couldn't decide which shirt I wanted to draw on him so i drew all three cut them out and taped the edges, when i'm tired of looking at the "vote for pedro" shirt, I would just simply flip and fold a shirt on top of the paper and place it back in the frame. I often get tired of looking at my samples, this was just another way of solving my problem.
airbrush sketching is a technique my good friend Blake Souffrant (Master airbrush painter) taught me today. It's a great way to practice with your "airbrush control" it's also a great way to warm up!