Script makes plane point in general direction but doesn't point fully... read description please!

So I wrote this simple AI script for an airplane to move between waypoints, and wrote my thinking in the comments. However, after the plane destroys the 1st waypoint, it moves partially into the direction of the 2nd waypoint, but never hits the 2nd waypoint. So while it is moving slightly into the right direction… it never actually hits Waypoint2. What am I doing wrong? THANK YOU SO MUCH!

using UnityEngine;
using System.Collections;

public class AICustomScript : MonoBehaviour
{
//first waypoint
    public Transform Waypoint;
//second waypoint
    public Transform Waypoint2;


    void Start()
    {
        rb = GetComponent<Rigidbody>();
//make plane point in direction of first waypoint
        transform.LookAt(Waypoint);
    }
//allow me to select amount of force in editor
    public float AddForceAmount;
//allow me to select plane in editor
    public Rigidbody rb;

   /void FixedUpdate()
    {
//make plane move
        rb.AddForce(transform.forward * AddForceAmount);
    }
//PART OF CODE TO DETECT ARRIVAL ON WAYPOINT
    void OnTriggerEnter(Collider other)
    {
        if (other.gameObject)
        {
//destroys waypoint
            Destroy(other.gameObject);
//makes plane look at 2nd waypoint (Waypoint2)
            transform.LookAt(Waypoint2);
        }
    }
}

//SO WHAT'S WRONG?

Hi DroidifyDevs,

I think your problem is with physics.

I tried this script, and it worked fine as long as my player object started on the line which would connect the two waypoints. If it was not on that line it would not. Basically, what’s happening is that your plane turns to look at the first waypoint and you add a force along that vector. Once that waypoint is destroyed, your plane turns to look at the second waypoint, and you add a force along that vector. However, your plane is still carrying the momentum from your original force, so the new force gets added to the existing momentum and your plane, while pointed in the right direction, will actually move in a direction resulting in the sum of the two vectors.
89656-forces.png
Unfortunately, I’m not adept enough at the Unity engine yet to know how to procedurally negate a rigidbody force. This is something I’m trying to figure out too.

If anyone out there can take this one step further, I’m sure DroidifyDevs will appreciate it as much as I will.