Catherine Stinson was an early female aviation pioneer, being only the 4th woman to earn her pilot’s licence in the United States (in 1912). By 1915 she was a flying instructor, aviation aerobatics performer and was flying a Curtis biplane on exhibitions to raise funds for the American Red Cross. By 1917 she was driving ambulances for the Red Cross on the Western Front.
She certainly had the finances, if she’d wanted, to get herself and an aircraft to France by 1915 and volunteer for the French Aviation Corps. Given France’s desperate straits at the time, she probably would not have been rejected, and with her prior experience she would have had a good chance of becoming an early Ace. With air combat in its infancy, still seen as novel and romantic, women pilots performing well in this new field may have resulted in it being accepted as the norm. Given that women withstand Gee forces better than men, and are generally of shorter stature, having them available to recruit from would have been a substantial advantage.