Their primary structure is a jointed, flat plastic skeleton from the dollar store.
I made their flight suits by wrapping each body in a silver plastic table cloths from the party supply store, then trimming to size and stapling them along the seams. The suits are decorated with craft paint, which added color, dimension and shine.
Their heads are basic paper maiche, using small balloons and paper towels instead of the usual tissue paper. The heads dried incredibly textural (which was expected), lumpy and misshapen (very unexpected) -- probably because I tried to remove the balloons before the exteriors were completely dried -- luckily, it was fine for this application. I painted the heads with regular craft paint, and enhanced the eyes by hot-gluing on the lenses I'd removed from cheapie sunglasses. I really like how they each have their own personality.