Plastic has been replacing aluminum in a widening array of military equipment because it offers equal protection at less weight  A plastic-armored vehicle is, however, twice as costly to make as an aluminum-armored vehicle
Ttherefore, the replacement of aluminum-armored vehicles by plastic-armored vehicles that offer equal protection is not yet advisable from a financial point of view
Although the cost of plastic is expected to remain stable, the growing practice of recycling metals will probably drive down the cost of metals.