The collection consists of letters sent from training stations during World War II documenting U.S. Army Air Force practices on a nearly daily basis. Letters have been foldered by month and year.

Addressed to "folks," the letters start from Sheppard Field, Texas, with the 31st Training Group. Mayer then moved to the 317th College Training Detachment at Montana State University in Missoula, Montana, where in October he and his unit had a bout of ptomaine poisoning [Oct. 27, 1943]. After flight officer training, Mayer was transferred to Squadron 32 at the Santa Ana Army Air Base in Santa Ana, California, in late December. Letters from Santa Ana include mentions of quarantines, washing out, and daily schedules, as well as psychological tests, aptitude tests, and high altitude [low air pressure] tests with and without oxygen masks. Mayer mentions dancing with Shirley Temple [Feb. 14, 1944] and meeting the actress Ann Rutherford.

For gunnery training Mayer moved to Kingman, Arizona in May 1944, learning to use and maintain .50 caliber machine guns. He was next stationed at the Army Air Forces Navigation School in Hondo, Texas [June 27, 1944], near San Antonio. After a brief period in Omaha and Lincoln in October, he moved to Casper, Wyoming, to train on B-24s. His final stateside letter mentions shipping out by way of Topeka, Kansas. A single "V mail" letter from England in April completes the collection.