This really is a scheme for free hand airbrush work and therfore depends if your airbrush is capable of the task. Assuming it is, then you will need to have the paint very thin, so that it will flow easily, have the air pressure very low, so that the thin paint isn't spattered everywhere, you will need to get in close and you need a steady hand. What I do is try and imagine that I am trying to spray to scale, but without a good airbrush you wont be able to get fine enough. This scheme would be posible with a single action syphon fed brush such as a Badger 200, but it will be a doddle with a gravity fed double action brush, such as a Simair Evolutin. (I have them both :-) ) I'm thinking 1/48 here, I't would be possible in 1/144 with the Evolution. It might just be possible with an Aztek, in 1/48.
Camo masks are great but there are none, that I know of that will give you this particular mottle. As almost if not all Luftwaffe aircraft, that had mottle, had different mottle, then the only "real" solution is freehand. I believe it's worth acheiving this skill anyway, so my advice,as Martin says is to practice. If you really want to do this scheme spend some quality time with your airbrush, get used to how the paint works with different amounts of thinner and air pressure. Practice this scheme, it's little arcs and flicks, until you are happy then go for it. If you put down a coat of Klear(Future), after the main part of the scheme is on, you'll be able to wipe it off if all goes wrong. You could if you wanted to draw the mottle on, that's what I did with my Tropical Stuka, you then don't have to think about it, or keep refering to the picture. It will take time, the green camo on my stuka took me a couple of hours or more over several sittings.
As a novice with an airbrush you may want to try masks though, but ther can be nothing more satisfying than achieving a difficult scheme, like this, freehand. It will always look better. Best of luck :-)
Mal