Able to jump in air? (Reward)

Hi, I am making a 2D game, and for some reason my player is able to jump while in the air. I don't want the player to. The player should only be able jump once, then able to jump again, when he lands on the GROUND. I am using the scripts from Unity Standard Assets, but edited some of them.

Here are the scripts that I think are relevant to my problem:

 using System;
 using UnityEngine;
 using System.Collections;
 using UnityEngine.SceneManagement;
 
 // Just in case so no "duplicate definition" stuff shows up
 namespace UnityStandardAssets.Copy._2D
 {
     public class PlatformerCharacter2D : MonoBehaviour
     {
         [SerializeField] private float m_MaxSpeed = 10f;                    // The fastest the player can travel in the x axis.
         [SerializeField] private float m_JumpForce = 400f;                  // Amount of force added when the player jumps.
         [SerializeField] private bool m_AirControl = false;                 // Whether or not a player can steer while jumping;
         [SerializeField] private LayerMask m_WhatIsGround;                  // A mask determining what is ground to the character
 
         private Transform m_GroundCheck;    // A position marking where to check if the player is grounded.
         const float k_GroundedRadius = .2f; // Radius of the overlap circle to determine if grounded
         public bool m_Grounded;            // Whether or not the player is grounded.
         private Animator m_Anim;            // Reference to the player's animator component.
         private Rigidbody2D m_Rigidbody2D;
         private bool m_FacingRight = true;
         public string GameOverScene;
         // For determining which way the player is currently facing.
 
         private void Awake()
         {
             // Setting up references.
             m_GroundCheck = transform.Find("GroundCheck");
             m_Anim = GetComponent<Animator>();
             m_Rigidbody2D = GetComponent<Rigidbody2D>();
         }
 
 
         private void FixedUpdate()
         {
             m_Grounded = true;
             // The player is grounded if a circlecast to the groundcheck position hits anything designated as ground
             // This can be done using layers instead but Sample Assets will not overwrite your project settings.
             Collider2D[] colliders = Physics2D.OverlapCircleAll(m_GroundCheck.position, k_GroundedRadius, m_WhatIsGround);
             for (int i = 0; i < colliders.Length; i++)
             {
                 if (colliders[i].gameObject != gameObject)
                     m_Grounded = true;
             }
             m_Anim.SetBool("Ground", m_Grounded);
         }
 
 
         public void Move(float move, bool jump)
         {
             //only control the player if grounded or airControl is turned on
             if (m_Grounded || m_AirControl)
             {
                 // The Speed animator parameter is set to the absolute value of the horizontal input.
                 m_Anim.SetFloat("Speed", Mathf.Abs(move));
 
                 // Move the character
                 m_Rigidbody2D.velocity = new Vector2(move*m_MaxSpeed, m_Rigidbody2D.velocity.y);
 
                 m_MaxSpeed += 0.5f * Time.deltaTime; /////////////////////////////////////////////////////////////////////////////////
 
                 m_JumpForce += 1.0f * Time.deltaTime; ////////////////////////////////////////////////////////////////////////////////
 
                 m_Rigidbody2D.gravityScale += 0.009f * Time.deltaTime; /////////////////////////////////////////////////////////////
 
 
                 // If the input is moving the player right and the player is facing left...
                 if (move > 0 && !m_FacingRight)
                 {
                     // ... flip the player.
                     Flip();
                 }
                     // Otherwise if the input is moving the player left and the player is facing right...
                 else if (move < 0 && m_FacingRight)
                 {
                     // ... flip the player.
                     Flip();
                 }
             }
             // If the player should jump...
             if (m_Grounded = true && jump && m_Anim.GetBool("Ground"))
             {
                 // Add a vertical force to the player.
                 m_Anim.SetBool("Ground", false);
                 m_Rigidbody2D.AddForce(new Vector2(0f, m_JumpForce));
             }
         }
 
 
         private void Flip()
         {
             // Switch the way the player is labelled as facing.
             m_FacingRight = !m_FacingRight;
 
             // Multiply the player's x local scale by -1.
             Vector3 theScale = transform.localScale;
             theScale.x *= -1;
             transform.localScale = theScale;
         }
 
         void OnCollisionEnter2D(Collision2D target)
         {
             if (target.gameObject.tag == "Enemy") {
                 m_MaxSpeed = 0f;
                 m_JumpForce = 0f;
                 m_Rigidbody2D.gravityScale = 20f;
 
 
 
             }
     }
 
 
         IEnumerator DelayedSceneLoad()
         {
             yield return new WaitForSeconds(1.5f);
             SceneManager.LoadScene(GameOverScene);
 
         }
 
 
 }
 
 
 }



 using UnityEngine;
 using UnityStandardAssets.CrossPlatformInput;
 
 // Just in case so no "duplicate definition" stuff shows up
 namespace UnityStandardAssets.Copy._2D
 {
     [RequireComponent(typeof (PlatformerCharacter2D))]
     public class Platformer2DUserControl : MonoBehaviour
     {
         private PlatformerCharacter2D m_Character;
         private bool m_Jump;
 
 
         private void Awake()
         {
             m_Character = GetComponent<PlatformerCharacter2D>();
         }
         
         private void Update()
         {
             if (!m_Jump)
             {
                 // Read the jump input in Update so button presses aren't missed.
                 m_Jump = CrossPlatformInputManager.GetButtonDown("Jump");
             }
         }
         
         private void FixedUpdate()
         {
             float h = CrossPlatformInputManager.GetAxis("Horizontal");
             // Pass all parameters to the character control script.
             m_Character.Move(h, m_Jump);
             m_Jump = false;
         }
     }
 }

Anyone that helps will be rewarded with karma/reputation points, just to be nice. :)