Hamilton "Ham" Coolidge (1895-1918) was one of many young men from wealthy New England families who enlisted during World War I. Coolidge served as a pilot with the U.S. Army Air Service 94th Aero Squadron. He achieved Ace status, was awarded the Distinguished Service Cross, and was killed in action. The collection contains materials related to Coolidge's military service.

Harold A. McGinnis (1893-1986) served in the U.S. Army Signal Corps, Aviation Section as a pilot during World War I and remained in the military until his retirement in 1948. The collection contains pilot log books relating to World War I and photographs relating to World War I and pre-World War II era military aircraft.