need help making a simple ascending enemy

So as the question says, i want to make an enemy that simply ascends after some seconds. I achieve this by using a coroutine. But when it comes to the actual code of making the enemy fly, and follow along beneath the ceiling i'm running into issues. I'm doing a raycast check that if it collides with the ceiling, it moves to the right.

The way im making it fly, is by after 2 seconds i set the gravity to -2, so it levitates into the air untill the raycast hits the ceiling, and then it moves right. But i want it to move back to the left, when it's out of the colliding bounds. My code is as follows:

 public Transform sightStart, sightEnd, flyUpSight;
     public float speed = 15;
     public bool moving = false;
     public bool needsCollision = true;
     public bool collision = false;
     public LayerMask whatIsColliding;
     public Transform groundcheck;
     public bool grounded = true;
     public float groundRadius = 0.2f;
     public LayerMask whatIsGround;
     public bool flying = false;
     public int groundSpeed = 5;
     public bool flyCollision = false;
     public float flyingSpeed = 1;
     void FixedUpdate()
     {
         StartCoroutine ("Fly");
         Moving ();
 
     }
 
 
     private IEnumerator Fly()
     {
         yield return new WaitForSeconds (2);
         FlyUp ();
         flying = true;
         moving = false;
         //grounded = false;
         groundSpeed = 0;
         //needsCollision = true;
         rigidbody2D.gravityScale = -2f;
     }
 
     void Moving()
     {
         grounded = Physics2D.OverlapCircle (groundcheck.position, groundRadius, whatIsGround);
         
         rigidbody2D.velocity = new Vector2 (transform.localScale.x, 0) * groundSpeed;
         collision = Physics2D.Linecast (sightStart.position, sightEnd.position, whatIsColliding);
         Debug.DrawLine (sightStart.position, sightEnd.position, Color.green);
         if (collision == needsCollision) 
         {
             this.transform.localScale = new Vector3(( transform.localScale.x == 1) ? -1 : 1,1,1);
         }
     }
 
     void FlyUp()
     {
 
         flyCollision = Physics2D.Linecast (sightStart.position, flyUpSight.position, whatIsColliding);
         Debug.DrawLine (sightStart.position, flyUpSight.position, Color.green);
 
         if (flying) 
         {
             if(flyCollision || collision == true)
             {
                 transform.Translate (Vector3.right * flyingSpeed);
 
                 if((flyCollision == needsCollision))
                 {
                     this.transform.localScale = new Vector3(( transform.localScale.x == 1) ? -1 : 1,1,1);
                 }
             }
         }
     }

EDIT: so i went ahead and hardcoded it, and now i have a very funny function, it flies up and down and goes around the block

 void FixedUpdate()
     {
         rigidbody2D.velocity = new Vector2 (transform.localScale.x, 0) * speed;
         collision = Physics2D.Linecast (sightStart.position, sightEnd.position, whatIsColliding);
         Debug.DrawLine (sightStart.position, sightEnd.position, Color.green);
 
         if (collision == needsCollision) 
         {
             this.transform.localScale = new Vector3 ((transform.localScale.x == 1) ? -1 : 1, 1, 1);
         }
 
         StartCoroutine("FlyUp");
 
     }
 
     private IEnumerator FlyUp()
     {
         yield return new WaitForSeconds (1);
         transform.Translate (Vector3.up * 0.1f);
         yield return new WaitForSeconds (2);
         transform.Translate (-Vector3.up * 0.5f);
         yield return new WaitForSeconds(2);
         StopCoroutine ("FlyUp");
     }