Slowing player speed when in air

Hello all;

I am currently moving my player (a Ball) with Force, however when in the air I realise that the Ball is no longer being slowed down by the friction below it, which means the speed of the ball is greatly increased while jumping, I would actually like the player to move slower while in the air.

I have tried many IF statements, but this one has stumped me.

Code:

 function Update(){ 
     var hit : RaycastHit; 
         if (Physics.Raycast (transform.position, Vector3.down, hit, 2.5)) { 
               if (isFalling==false && Input.GetButtonDown("Jump")){  
             rigidbody.velocity.y += jumpSpeed; 
         } 
     } 
      
 } 
  
  
 function FixedUpdate(){ 
     if(Input.GetKey ("right")) { 
             rigidbody.AddForce (cameraRelativeRight * Speed * Time.deltaTime); 
     } 
     if(Input.GetKey ("left")) {
         rigidbody.AddForce (cameraRelativeLeft * Speed * Time.deltaTime);
         }
 } 
 function Jump (){ 
         if (Input.GetButtonDown("Jump") && isFalling==false){ // only jump from the ground 
         jumped = true; 
         var hitt : RaycastHit; 
         rigidbody.AddForce.y (jumpSpeed * Time.deltaTime); 
         } 
     }

Any ideas would be greatly appreciated, thank you.