Marine Corps One is the designation of the
helicopter the President is on. The Marines at HMX-1 fly the President in helos. I have flown with them a bunch.
The main Presidential helo, the one you see, is an H-3 Seaking. It does not go over seas with the President.
The H-60 does go over seas and folds and stuffs into the transport aircraft. Onboard ship.
It folds and stuffs like you read about.