Adding MidAir Movement to Default Third Person Character

I want to modify the Third Person Controller character from Standard Assets to control more like a 3D platform character like in Super Mario 64 and the like.

However, I’ve noticed that you have no movement control besides turning while airborne.

I have tried as this article suggested by removing some IsGrounded() checks, but nothing has changed. I’ve tried the same thing for enabling Animator.applyRootMotion.

void HandleGroundedMovement(bool crouch, bool jump)
		{
			// check whether conditions are right to allow a jump:
			if (jump && !crouch && m_Animator.GetCurrentAnimatorStateInfo(0).IsName("Grounded"))
			{
				// jump!
				m_Rigidbody.velocity = new Vector3(m_Rigidbody.velocity.x, m_JumpPower, m_Rigidbody.velocity.z);
				m_IsGrounded = false;
				m_Animator.applyRootMotion = true;
				m_GroundCheckDistance = 0.1f;
			}
		}

I relayed this to a friend who said that this code is more reliant on the Animator. Unfortunately, I have very little experience with using the Animator.

What can I do to easily modify the Third Person Character to add more flexible movement?

Did you ever find an answer to this?