As Plisken escapes in the hijacked chopper, Quervo Jones picks up a bazooka and prepares to fire on it. As Fast Eddy shoots him through the chest, watch the bazooka. You can see right through the barrel. In other words, there is no ammo in the weapon.
Kurt Russell kept the outfit he wore in Escape from New York. The very first day of shooting Escape from L.A., he stepped out of his trailer in that very same outfit for shooting. He and producer Debra Hill looked at each other and began laughing. Debra Hill said it was like going into a time machine.