"Don't Ask, Don't Tell" indeed! From Flickr:
This patch is from the 22nd Military Airlift Squadron, who flew C-5 cargo aircraft out of Travis Air Force Base in Northern California. Part of the 22nd MAS’ mission was to conduct late night operations picking up classified aircraft from aerospace plants in Southern California and delivering them to classified locations for testing and evaluation. When the 22nd MAS undertook these missions, its crews would take off their everyday heraldry and Velcro this patch to their uniforms. The black background and crescent moon on the patch probably represent the unit’s night operations. The silver lining represents star light. The question mark signifies classified operations. The letters “NOYFB” stand for “None of Your F$*!ing Business.”
But what do you think it all means? Leave your thoughts & explanations in the comments!