On the 'lighter side' of that same recommendation, I'll put in a plug for one of my all-time favorite scratchbuilding materials, what I call 'pie plate aluminum.' The pie tins or foil trays you get with freezer meals, store-bought pastries, etc. It has most of the same qualities Don mentioned above -- though easier to cut, with scissors, hobby knives or even razor blades -- and easy to drill and work. By rolling it over convex or concave shapes, you can even impart limited compound curves.
Uses are almost limitless. Seat harness buckles and connectors. Data plates for cockpit panels, gear struts, etc. (Dab paint on, then scratch off with a needle to do borders and 'writing.') All sorts of cockpit stuff, like switches, covers, brackets, housings and map cases. Scale-thickness access panels, missile fins, ammo feed chutes, AOA indicators, the list goes on and on.
Super useful stuff! 
