Adding a bigger fairing will increase the cross section of the object, increasing the form drag. (Bigger things push more air out of their way when moving)<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Parasitic_drag#Form_drag" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Parasitic_drag#Form_drag</a>