Why doesnt my script work

So im making an action game, well, it does have planes and i made a plane controller, it comes successfully but then i found a problem,

My plane wont go forward

Here's my script

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class Move : MonoBehaviour { public float power; public GameObject plane;

 private Rigidbody rb;

  void Start()
 { 
     rb = GetComponent<Rigidbody>();
 }

  void FixedUpdate()
 {
     bool isA = Input.GetKey(KeyCode.A);
     bool isD = Input.GetKey(KeyCode.D);
     bool isRight = Input.GetKey(KeyCode.RightArrow);
     bool isLeft = Input.GetKey(KeyCode.LeftArrow);
     bool isForward = Input.GetKey(KeyCode.T);
     bool isUpArrow = Input.GetKey(KeyCode.UpArrow);
     bool isDownArrow = Input.GetKey(KeyCode.DownArrow);

     Vector3 rotZ = new Vector3(0.0f, 0.0f - 0.1f);
     Vector3 rotY = new Vector3(0.0f, 0.2f - 0.0f);
     Vector3 rotX = new Vector3(0.1f, 0.0f - 0.0f);

     if (isRight == true)
     {
         plane.transform.Rotate(rotZ);
     }
     else if (isLeft == true)
     {
         plane.transform.Rotate(-rotZ);

     }
     if (isDownArrow == true && plane.transform.rotation.x <= 90)
     {
         plane.transform.Rotate(rotX);
         plane.transform.Rotate(rotX);
         
     }
     else if (isLeft == true && plane.transform.rotation.x >= -90)
     {
         plane.transform.Rotate(-rotZ);
        

     else if (isForward == true)
     {
         rb.AddRelativeForce(Vector3.right * power * -100);
     }
     else if (isDownArrow == true)
     {
         rb.AddRelativeForce(Vector3.right * power * -100);
         plane.transform.Rotate(-rotX);
     }
      else if (isUpArrow == true)
     {
         rb.AddRelativeForce(Vector3.right * power * -100);
         plane.transform.Rotate(rotX);
     }
 }

}

I was trying to change t$$anonymous$$ngs to find what went wrong and my script took a turn for the worst...

What have i missed to make my plane go forward