You can easily use Area Triggers to make it so that if the player is on the BH, it takes off - but what if the player is in the Area Trigger while the BH is not on the trigger? (So if I step in the trigger while the BH is not in the trigger, it might cause the BH to follow its waypoints from the start again.)
So teleport markers might need to be required as well.
You should make a tutorial Jckl.
Chris