I have a script that controls an aeroplane. Currently, when I completely turn around it keeps going backwards untill it stops and accelerates forward. This is, as you can imagine, extremely unrealistic. I have no idea how to remove momentum. Any help?

var maxTorque : float = 10.0f;
var forwardForce : float = 10.0f;

var currentTorqueHor : float = 0.0f;
var currentTorqueVer : float = 0.0f;
var currentTorqueBank : float = 0.0f;

function Update()
{
    currentTorqueHor = maxTorque * Input.GetAxis("Horizontal"); 
    currentTorqueVer = maxTorque * Input.GetAxis("Vertical");
    currentTorqueBank = maxTorque * Input.GetAxis("Bank");
    }

function FixedUpdate()
{   
    rigidbody.AddForce(transform.forward * forwardForce);
    rigidbody.AddRelativeTorque(currentTorqueVer, currentTorqueBank, -currentTorqueHor);
}