Character moving up/down & left/right while constantly going forward in Z

I'm attempting to create a 'flying' character that the player can move up or down on the y axis and left or right on the x axis, while constantly moving forward in the z axis.

The problem I'm seeing is that the player gets 'stuck' for lack of a better term on the x axis. The model will move a few pixels to the right, for example, then stop while still being able to move over to the left without issue. What I don't understand is why the player moving on the y axis isn't doing the same thing.

WEB PLAYER http://acjcllc.com/unity/WebPlayer/WebPlayer.html

This is the script I'm using:

var speed:float = 10.0;

private var thisTranform:Transform; private var thisCharacter:CharacterController;

function Start () { thisTranform = GetComponent(Transform); thisCharacter = GetComponent(CharacterController); }

function Update() { dir = new Vector3( Input.GetAxis("Horizontal") Time.deltaTime speed, Input.GetAxis("Vertical") Time.deltaTime speed, 0.25 ); Debug.Log(dir); thisCharacter.Move(dir); }

NOTE: The player is controlled with a Character Controller, not a Rigidbody. I've tried both FixedUpdate and Update without any change in behavior.

Any idea of why this is happening? Or, if there is a better way to do it, how? Links to tutorials / explanations appreciated.

Thanks!