A candid variant among a series of group portraits taken of a U.S. Army Air Service detachment at Mather Field, California, during World War I. Several men in the front rows can be seen smiling for the camera, offering a rare glimpse of levity amid the formal record-keeping typical of military unit photography from this era. The image forms part of a broader set documenting the young men who trained at this Sacramento-area airfield in 1918. Project: 218714