During the Second World War, several women's organizations that dealt with aviation in some way were formed as part of the women's war effort.
For example, the best instance of this is actually in America, where there was an organization called the Women Airforce Service Pilots (WASP), which started after women pilots came to fulfill the ranks left by a shortage of male pilots. A group of women was assembled under the leadership of Jacqueline Cochran who brought together a group of women to be trained to fly aircraft in accordance with military training and regulations. The women she brought together then formed the organization WASP and became the first women to have military authorization and training to fly.
In Britain, there was the Women's Royal Air Force, which was a precursor to the Women's Auxiliary Air Force. The former organization formed during the First World War and was plagued with leadership difficulties. Finally, Helen Gwynne-Vaughan took over the leadership of the organization and successfully ran it until it was disbanded after World War I. Unlike WASP, the positions women held in WRAF were more secretarial, requiring that the women act as clerks, fitters, waitresses, telephone operators, drivers, cooks and storekeepers. In this manner, they were able to free up men to be used as pilots since the secretarial jobs were now being filled by the women.
During the Second World War, the Women's Auxiliary Air Force was formed (which, incidentally, Gwynne-Vaughan was asked to lead, but she turned down the offer). As with the Women's Royal Air Force, women were not given the job of pilots (since they were basically filling positions to free up men to fly), but were asked to contribute in other ways, from telephone operators to women who worked on intelligence. Interestingly, the WRAF was reinstituted and synthesized later with the WAAF.
However, there were apparently some women pilots, as evidence by the British woman pilot Amy Johnson. She gained quite a bit of commercial flying experience before war broke out and used this experience to join the Air Transport Auxiliary since she was not able to join the Royal Air Force (the men's branch, in which they can actually fly).