Attaching player control script at runtime

I need to attach a player controller script to a prefab at and have it be able to communicate with all of the other scripts attached to that prefab. The problem I am having is that (for example) the player could select any plane but each plane could have a different way to fire projectiles. So the player controller needs to be as generalized as possible. This is the start I had:

     public class Player_Controller : MonoBehaviour {
         void Update () {
             gameObject.SendMessage ("set_thrust", Input.GetAxis ("Throttle"));
         }
     }

 public class Ship_Controller : MonoBehaviour {

 public float max_Speed;
 public float cur_Speed;
 
 public float rotation_Speed;
 public float max_Accel;
 public Quaternion add_Rotation;

 public float thrust;

 public float pitch_Axis;
 public float roll_Axis;
 public float thrust_Axis;

 protected Rigidbody _rb;

 public void Start() {
     cur_Speed = 10.0f;
     max_Speed = 500.0f;
     max_Accel = 50.0f;

     // Rotation
     rotation_Speed = 100.0f;
     add_Rotation = Quaternion.identity;
     pitch_Axis = 0f;
     roll_Axis = 0f;
     thrust_Axis = 0f;

     // Componenets
     _rb = GetComponent<Rigidbody> ();
 }

 void Update() {
     thrust_Axis *= max_Accel;
     
     cur_Speed += thrust;
     
     if (cur_Speed > max_Speed) {
         cur_Speed = max_Speed;
     }
 }

 protected void set_thrust(float num) {
     thrust_Axis = num;
 }

}