How Make Animations Activate only When Airborne?

I’ve been learning how to create a 2D character and use the animator, and things have been going pretty well, u n t i l it came to figuring out how to make an animation only active when in the air. Here is the Animator script for reference:

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

public class CharacterAnim : MonoBehaviour {

    private Animator anim;

    private PlayerController controller;

    void Start(){
        anim = GetComponent<Animator> ();

    }
       
    void Update(){
        if (Input.GetKey (KeyCode.LeftArrow) || Input.GetKey (KeyCode.RightArrow)) {
            anim.SetBool("isRunning", true);
        } else {
            anim.SetBool ("isRunning", false);
    }

        if (Input.GetKeyDown (KeyCode.UpArrow)) {
            anim.SetTrigger("jump");
        }

        if (controller.isGrounded) {
            anim.SetBool ("isJumping", true);
        }
  }
}

And, in case it may be needed, here’s the Player Controller Script for reference as well:

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

public class PlayerController : MonoBehaviour {

    public float speed;
    public float jumpforce;
    private float moveInput;

    private Rigidbody2D rb;

    private bool facingRight = true;


    private bool isGrounded;
    public Transform groundCheck;
    public float checkRadius;
    public LayerMask whatIsGround;

    private int extraJumps;
    public int extraJumpValue;


    void Start(){
        extraJumps = extraJumpValue;
        rb = GetComponent<Rigidbody2D> ();
    }

    void FixedUpdate(){

        isGrounded = Physics2D.OverlapCircle(groundCheck.position, checkRadius, whatIsGround);


   
        moveInput = Input.GetAxis ("Horizontal");
        rb.velocity = new Vector2 (moveInput * speed, rb.velocity.y);

        if (facingRight == false && moveInput > 0) {
            Flip ();
        } else if (facingRight == true && moveInput < 0) {
            Flip ();
        }
    }

    void Update(){

        if (isGrounded == true) {
            extraJumps = extraJumpValue;
        }

        if (Input.GetKeyDown (KeyCode.UpArrow) && extraJumps > 0) {
            rb.velocity = Vector2.up * jumpforce;
            extraJumps--;
        } else if (Input.GetKeyDown (KeyCode.UpArrow) && extraJumps == 0 && isGrounded == true) {
            rb.velocity = Vector2.up * jumpforce;
        }
           
    }
    void Flip(){

        facingRight = !facingRight;
        Vector3 Scaler = transform.localScale;
        Scaler.x *= -1;
        transform.localScale = Scaler;
    }

}

Again? You have already created one thread about that.

Oh, this one was refusing to upload, so I tried just making a new thread. Apparently, it finally uploaded the first one, so I can go back and delete that other one.