When laying out your work, you need a flat copy of the curved surfaces. IE if you take a top view and use is to lay out the pattern on a wing, the pattern will come up short in the cord. How much depends on the airfoil. For the fuselage, it is quite a problem trying to make a pattern from a side view. The best bet is to use a drawing / CAD program that lets you make a "sheet" of the curved surface. You can then put your pattern on the sheet, then when the sheet is curved around the wing or fuselage, the ends of the pattern end up where you wanted them. Another lower tech was would be to use butchers paper and cover the model with it, taping pieces down as you go with blue masking tape, Then tape all the seams and lift the paper off. This is your "Sheet' to lay out the pattern.

Don