Harmon was a 24-year-old nursing school graduate when she was hired in 1940 as a Delta stewardess. Back then, stewardesses were required to be registered nurses.
Since then, stewardesses have become known as flight attendants, Delta has grown into one of the largest airlines in the world and Harmon's flight logbooks have been preserved by the Delta Flight Museum.
She worked for Delta from 1940 to 1943, flying mainly on the 21-seat DC-3, before leaving the airline to join the war effort.
She then married U.S. Army Capt. Wallace Harmon, a former Delta reservations agent who eventually became a district director of traffic and sales in Dallas. Their daughter Peggy worked as a Delta flight attendant from 1973 until 2008.
Delta threw a 102nd birthday party for Harmon last year at her retirement home in Acworth. Chief Executive Officer Ed Bastian recorded a birthday message thanking her "for all you did to put Delta on the map."
On Tuesday, Delta issued a statement saying, "We're saddened to learn of Sybil Peacock Harmon's passing. Sybil was a beloved member of the Delta family who left her mark as a member of our first class of flight attendants. We will cherish her memory and wish her loved ones well in this difficult time."