Sierra Hotel Aeronautics (SHA) Phonetic abbreviation for “shit hot", The highest praise; the pilot’s favorite and all-purpose expression of approval from fellow aviators. Wearing the Sierra Hotel Crew Cap is a declaration of your personal pursuit of aeronautical excellence.
During wartime, flight crews quickly discovered that baseball caps not only provided better protection from the glaring sun when spotting enemy aircraft, but also enabled a more comfortable fit under their headsets. Long missions under the sun soaked canopy caused fatigue and a reduction of flight crew readyness. For this reason many crews began to fly with baseball caps in the Pacific Theater of Operations.
During the Second World War, St. Louis Cardinals manager Billy Southworth received a unique handwritten request.
It seems that a commander of a Marine fighter squadron in the Pacific made an offer to Southworth that he could not refuse. If the St Louis Cardinals sent baseball caps to his squadron based in the South Pacific, he and his pilots would guarantee to shoot down one Japanese fighter for each cap received.
Southworth agreed, and sent a box of 20 caps to the island of VellaLavella. By early 1944, Southworth learned that the Marine Squadron had splashed 48 Zeros, and that number was still climbing. The Cardinals manager later discovered that the Commander that made the request, was none other than Maj. Gregory "Pappy" Boyington and the squadron was no less than the famed VMF-214 "Black Sheep Squadron."