U.S. WWII USAAF Air Crew Cap Heavy Type D1-A This cap is just post-WWII and is used with an A-1A flying shirt and E-1A trousers. Like most clothing from the period just post WWII, all these items came in blue, green, and sage green. The green clothing usually had no suffix, such as "D-1", the blue clothing usually had an "A" such as D-1A, and the sage green usually was "B". This example is in very good near mint condition & in Size Xlarge.