Does anyone know the origin of the character in Godfather I,.....I heard it was from a California character named John Peterson...Also was the helicopter scene in Godfather III written from a real event on the East Coast?

As far as I know, "Dominic Panza," the Don of Boston in the novel, is a completely fictitious character. He didn't have the respect of the other Dons because "he couldn't keep order in his empire"--too many free-lancers. This is also fictitious. Boston used to be Irish territory, but by the mid-'30's, the Mafia--first under Phil Buccola, then Joe Lombardo, then Raymond Patriarca--pretty much had things tied up. Boston did have some free-lance activities, but no more than in other cities. In fact, Patriarca was one of the more durable and effective Dons.