Trouble with flying charecter.

I'm trying to make a script that will allow my player to fly when isGrounded == false but when I test it the character is automatically flying. I thought it was the sphere collider that's on the bottom of the Unity Standard asset 3D character but that doesn't seem to be the case.

 bool isGrounded = true;
  
 // Use this for initialization
 void Start () {

 }
 
 // Update is called once per frame
 void FixedUpdate()
 {
     if (isGrounded == false)
         gameObject.GetComponent (typeof(CharacterController)); 

     {

         CharacterController cc = (CharacterController)gameObject.GetComponent( typeof(CharacterController));

         float rotateSpeed = 10.0f;
         float rotationY = Input.GetAxis ("Mouse X") * rotateSpeed;
         transform.Rotate (0 , rotationY , 0); 

         float moveSpeed = 20.0f;
         float dt = Time.deltaTime;
         float dy =  0;
         if(Input.GetKey(KeyCode.Space))
         {
             dy = moveSpeed * dt;
         }
         if(Input.GetKey(KeyCode.P))
         {
             dy -= moveSpeed * dt;
         }
         float dx = Input.GetAxis("Horizontal") * dt * moveSpeed;
         float dz= Input.GetAxis("Vertical") * dt * moveSpeed;

         cc.Move(transform.TransformDirection(new Vector3(dx, dy,dz))  );
     } 
 }
 void OnTriggerEnter()
 {
     isGrounded = true;

 }

 void OnTriggerExit()
 {
     isGrounded = false;
 }