My AI is flying when I jump

How can I change my script so the Enemy doesn’t fly when I’m above it?

var target : Transform; //the enemy's target
var moveSpeed = 3; //move speed
var rotationSpeed = 3; //speed of turning
var myTransform : Transform; //current transform data of this enemy
function Awake()
    myTransform = transform; //cache transform data for easy access/preformance
function Start()
     target = GameObject.FindWithTag("Player").transform; //target the player
function Update () {
    //rotate to look at the player
    myTransform.rotation = Quaternion.Slerp(myTransform.rotation,
    Quaternion.LookRotation(target.position - myTransform.position), rotationSpeed*Time.deltaTime);
    //move towards the player
    myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;

Instead of using target.position - myTransform.position to obtain the lookrotation, use another Vector3 that has the same vertical position of the enemy transform. Something like this:

Vector3 newTargetPosition = new Vector3(target.position.x, myTransform.position.y, target.position.z);

Then, use it in the Quaternion.LookRotation as this:

Quaternion.LookRotation(newTargetPosition - myTransform.position)

[EDIT] forgot to mention that my code is in C#…

Depending on your game, you could remove the y component of the movement vector:

Vector3 movement = myTransform.forward * moveSpeed * Time.deltaTime;
movement = new Vector3(movement.x, 0, movement.z);
myTransform.position += movement;

Or you could add a CharacterController to the AI, but that’s a tad bit harder and probably slower, but it would use the level geometry (if you have any).