Airman Magazine was founded in the 20th Century in the USA and was published bi-monthly.
1957 (1957) USA Bi-monthly Airman Magazine The 20th (twentieth) century began on January 1, 1901, and ended on December 31, 2000. The term is often used to refer to the 1900s, the century between January 1, 1900 and December 31, 1999. 
