This code shows the movement of the object fly according to the mouse movement

var flySpeed:Number = 0.1;

fly.addEventListener(Event.ENTER_FRAME,flyMove);

function flyMove(event:Event):void {

	var fly_x:Number = (mouseX - fly.x) * flySpeed;
	var fly_y:Number = (mouseY - fly.y) * flySpeed;
	var angle = Math.atan2(fly_y, fly_x);
	fly.x += fly_x;
	fly.y += fly_y;
	fly.rotation = 90 +(angle * 180 / 3.141593E+000);

}