Initial Flight of B-19 Bomber On Jun.27, 1941 Cover W/ Professional Form Letter. It was a world’s largest airplane at that time.Super-bomber for United States Army Air Corps. First flight from Clover Field , Santa Monica to March Field , Riverside, California.Enclosed was a note from the professional to the letter sender and a little from the professional about the story of the B-19 Bomber. Memorabilia collection. Free Shipped with USPS First Class Package.