Blue metal may refer to a plane. I've heard planes referred to as East Coast Metal and West Coast Metal during the merging of two airlines.
Blue metal may refer to a Navy plane??
Somebody up-thread suggested blue metal = Air Force 1. You provide more support for that theory.
Bagster
Blue metal may refer to a gun. "Blueing" is a protective metal treatment, a chemical which when applied to the steel components of a firearm, turns the metal's finish dark blue, almost black.