I'll start off with the aluminum one. First off I try to get a 3 view drawing and compare it to the dimensions. Usually, Luft46.com has good drawings and artwork to go by. I then blow up the 3 view to 1/72 scale and make a half dozen copies. I use these as templates for making the fuselage, wings, etc. The aluminum jet took more time because each piece had to be ground pneumatically to speed up the process. Here are some build up photos:
The shape was hand worked, and the cockpit and gear bays were setup on a milling machine and milled out.