Here are a few historical facts from the Int. Society of Women Airline Pilots' website:
*Helen Ritchey was the first documented and verified female pilot to be hired to fly as a pilot of a commercial scheduled passenger carrier when the U.S. carrier, Central Airlines, hired her on December 13, 1934. The pilots wouldn't allow her to join the all-male pilot union so she was forced to resign in October of 1935. We are currently investigating two other woman that may take Helen's place in history, Betty Russell - purported to be flying for Royle and Andrews Flying Service in 1930 out of Alameda, California, and Marga von Etzdorf, purported to have flown Junkers F-13's for Lufthansa in 1927.*
There are now women flying for airlines even intraditionally conservative counties/cultures such as Japan, Bangladesh and Nigeria.