Throughout the period 1900-1939 black Americans were actively involved in aviation. Until 1927 their participation was sporadic and their numbers limited. Between 1927 and 1936 black Americans' interest in aviation grew and several black pilots achieved notoriety through their aeronautical exploits. After 1936, the number of black Americans involved in aviation expanded and a national black flying association was established. Moreover, black Americans began to question discriminatory practices that restricted their opportunities in the air. Thus when the federal government expanded its involvement in civil and military aviation on the eve of World War II, the stage was set for the emergence of a powerful pressure campaign to prohibit racial discrimination in federally-funded aviation training and open the all-white U.S. Army Air Corps to black Americans.