Derp.
I don't understand what you mean.
If a rocket makes a hit, then the intense heat and explosive chemicals will melt a good portion of the dragon.
This is true, however. One shot from a dragon is a dead fighter plane. You can't debate about that since the fighter planes armour is a fact. The durability of a dragon can be debated. Speaking of which.
How strong do you believe the armour of the dragon is?
I don't think dragons set them self on fire on a regular basis.
I believe if they can have it on the inside, while remaining cool, they can have it on the outside.