http://media-cache-ak0.pinimg.com/originals/05/8a/f8/058af8ae7d7169f077fecaf8591b4fbc.jpg

I would love to create flames similar to the ones on the above cake but I can't wrap my brain around how to only airbrush the flames but not the rest of the cake... tape it off?

TIA

I would cut the flames out of a separate sheet of fondant, colour it and then wrap it round the cake.  You can see from the picture that it is two different bits of fondant - the underlayer is black, and then the flames laid over the top.

AYes, there are two layers of fondant - but only the flames have been airbrushed... I would think that if I airbrushed the flames BEFORE wrapping them around the cake the fondant would smudge/harden/crack so I think I need to airbrush it after the flames are in the cake...I just don't know how to airbrush only part of a cake... (Hope that makes more sense...)

Unless it takes you an awfully long time to airbrush, then it should be fine to spray then wrap.  It's not a complicated pattern to do, so it should be quick enough.  Most fondants don't set that quickly, especially if (as the picture shows) it's a reasonably thick layer.  Why don't you have a wee trial run and see?

^^I agree with Lizzie.

AI would cut te flames and wrap them around a cake pan or dummy. They will dry a bit but should be fine. Once the color dries (long before the fondant) transfer them to the cake. They will have the right curve to them from being on a pan/dummy