First off "Hooah!" and thanks brother, thanks to you and your family for the sacrifice. I know its not easy but just watch your 6, keep your head down and come home safe.
As far as the plastics. You can buy some very inexpensive molds from Bobs, Janns, Del-mart etc to start off with. Get a couple and get the feel of it. I get almost all of my plastic supplies from Del at del-mart. plastics, colors, glitter etc. There are a ton of great plastic threads to teach you the ropes. I prefer the microwave method as I dont pour in mass quantities.
As far as airbrushing. There are a lot of great brushes out there and it is endless at the things you can do. its all about imagination and most importantly, layers. I prefer a gravity fed airbrush and a compressor with a regulator. Experiment on old cranks, pvc pipe etc. Have your wife start saving old panty hose, loofas, netting etc.
I have to warn you up front that it will quickly become an obsession.
Again, thank you for taking the watch. You are a great American and a true Hero. Stay safe and we will see you on the water when you return brother.