Women have been involved in aviation from the beginnings of both lighter-than air travel and as airplanes, helicopters and space travel were developed. Women pilots were also formerly called "aviatrices" (singular "aviatrix"). Women have been flying powered aircraft since 1908; prior to 1970, however, most were restricted to working privately or in support roles in the aviation industry. Aviation also allowed women to "travel alone on unprecedented journeys". Women who have been successful in various aviation fields have served as mentors to younger women, helping them along in their careers.