Rockets Shooting up, negative number doesnt solve it

Trying to fire missiles from a jet but the missiles travel to the top of the map
Here is the code:
using UnityEngine;
using System.Collections;

public class RocketScript : MonoBehaviour
{

    public Rigidbody rocketPrefab;
    public Transform rocketLauncher1;
    public Transform rocketLauncher2;
    public Transform rocketLauncher3;
    public Transform rocketLauncher4;
    public float launchSpeed = 1;
    public Transform target;

    // Use this for initialization
    void Start()
    {

    }

    // Update is called once per frame
    void Update()
    {

        if (Input.GetButtonDown("Fire1"))
        {
            Rigidbody rocketInstance1;
            rocketInstance1 = Instantiate(rocketPrefab, rocketLauncher1.position, rocketPrefab.rotation) as Rigidbody;
            rocketInstance1.AddForce(transform.forward * -launchSpeed);
        }
    }
}

maybe the rotation makes transform.forward an upwards vector3? Try using quaternian.identity instead of prefab.rotation.