Many other illustrations in the site could be considered MIXED MEDIA. Some call it "mixed medium". There is almost always the use of brushwork or colored pencil in finishing airbrush illustrations. Or even a little airbrush for effect over top of a colored pencil illustration to smooth things out. I do a lot of watercolor or airbrush over pen & Ink. There are limitless combinations you could do. I am still having trouble with airbrush over soft pastel. For some reason my drawings keep disappearing!