I have an aeroplane that I can control. However, when it turns, it takes a while for its momentum to recede. If the plane turns in the opposite direction it flys backwards for a while before slowing and accelerating forward. This is extremely unrealistic, but I am new to Unity and can't figure it out.

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);
}