Historians have debated for decades the reasons for the spectacular failure of the Luftwaffe during the last three years of World War II. As the Luftwaffe went down in flames, the United States Army Air Forces arose to conquer the airspace on the Western Front of Europe. Before its downfall, Luftwaffe tactical airpower was key to Gen Heinz Guderian's surprise attack through the Ardennes to the English Channel in 1940. Similarly, in 1944, as Gen George S. Patton broke out of the Normandy beachhead by unleashing Operation Cobra, tactical airpower proved vital to his ability to march to the German border in only six weeks. This paper analyzes a host of primary sources authored by the main players in those campaigns (Guderian, Patton, and Weyland) and focuses on the key differences between the Luftwaffe support to Guderian and XIX Tactical Air Command support to Patton during their historic campaigns on the Western Front of Europe in World War II.