Those have to be water decals...I've seen some sick stuff with airbrush, but I seriously doubt that's airbrush....atleast, the motor and a bike aren't. The rest, sure. but if I was building a helmet, and doing progress pics like that, you could bet your ass it'd show it blank, then the motor, then the bike, etc...not justt he bike and motor already there...another reason why I believe those are decals.
I didn't even look at his other stuff, but it is pretty impressive now that I did look. Damn impressive actually. He needs a better camera, or photographer, cause those pictures probably do that artwork no justice, or, they really hide the flaws