Allowing a humanoid model to adopt scripts originally made for the player, how?

Hello, I am trying to make a mountable dragon, which can walk + fly.
I’ve got a simple script that allows for the player to do these, is there a way to:

Allow the model the player is sitting on (via seat and/or driverseat) to have the playerscript transfer onto it, allowing it to behave like the player would by pressing the required controls until the player jumps off the seat

Or anything that may be similar in outcome?
Or must the script be completely changed to make this dragon model move?

(The Dragon model has a humanoid, humanoidrootpart, and is rigged, and is a separate model from the player)