Why does my plane going up when my code is vector3.right, and when my code is vector3.forward why my plane is turning right

I’m studying create with code live and I have a little confused abt this function of two issue above and why does it that?
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerControllerX : MonoBehaviour
{
public float speed;
public float rotationSpeed;
public float verticalInput;

// Start is called before the first frame update
void Start()
{

}

// Update is called once per frame
void FixedUpdate()
{
    // get the user's vertical input
    verticalInput = Input.GetAxis("Vertical");

    // move the plane forward at a constant rate
    transform.Translate(Vector3.forward * speed * Time.deltaTime);

    // tilt the plane up/down based on up/down arrow keys
    transform.Rotate(Vector3.right * rotationSpeed * Time.deltaTime);
}

}

This is because Vector3.forward uses World position so this means if u turned 90 degrees forward is still de same as if u turned 0 degrees if u want to use local postion use tranform.forward @huyhoangtrank4ac