How do you use Add.Force() to fly in the mouse-inputted direction?

Hello!

I have been having trouble getting my plane to fly straight with the add.force command in javascript. My plane simply flies up really fast or straight down very fast and I cannot get it to go straight(or any horizontal direction). I have tried all of the solutions similar to rigidbody.AddForce(transform.forward * speed) and now I have resorted to thinking that I am missing something small yet detrimental. Please help!

var thrust: float; var rb: Rigidbody; var rotateSpeed = 30.0;

function Start() { if(GetComponent.().IsMine)//CAMERA { rb = GetComponent.(); Camera.main.GetComponent(Smoothfollow).target = transform; } }

function Update() {

if (GetComponent.().isMine) { var transAmount = thrust Time.deltaTime; var rotateAmount = rotateSpeed Time.deltaTime; Cursor.lockState = CursorLockMode.Locked; Cursor.visible = false;

 var h = -(Input.GetAxis("Mouse X")); 
  var v = -(Input.GetAxis("Mouse Y"));

 transform.Rotate(v, 0, h);      
 
 if (Input.GetKey ("w"))
 { 
     rb.AddForce(transform.forward * transAmount);
 }

}