It was a ballistic missile, not a SAM. It was a Sea Launched Ballistic Missile (SLBM).
Ballistic missiles are not used to shoot down aircraft.
How do we know it was an SLBM?
Because Q posted this:
I wikipedia’d SLBM and found that one kind of missile is an “M1” ... that rang a bell with the “FOX M1 STOLEN TAKEDOWN” post.