The daughter of Clyde and Bertha Williams Aitchison, Beatrice Aitchison was born in Portland, Oregon in 1908. Her mother was a musician and her father was a lawyer and economist who worked with the Interstate Commerce Commission. Aitchison graduated from Goucher College in 1928 and earned an M.A. and Ph.D. in mathematics from Johns Hopkins University in 1931 and 1933 respectively. She earned a master's degree in economics from the University of Oregon in 1937. During the 1930s, Aitchison taught mathematics, statistics, and economics at the University of Richmond, American University, and the University of Oregon; she also worked for the Works Progress Administration, the Department of Agriculture, and the Interstate Commerce Commission during this time. She taught at American University from 1942 to 1944 and also served as a consultant with the Office of Defense Transportation during World War II. From 1942 to 1951 she worked as a statistician and as an economist for the Interstate Commerce Commission. In 1953 she became director of transportation research in the Bureau of Transportation of the Post Office Department, thus becoming the most senior woman employed by the Postal Service. In 1961, she received the United States Civil Service Commission's Federal Woman's Award and in 1965 she was elected a Fellow of the American Statistical Association. She retired in 1971 and died in 1997.