Which skills and which industries please?
Any trade or industry that you could easily settle back into should your flying career suddenly take a turn for the worst. If you want to stay in a related field, remember that at its core, aviation is simply a transportation industry, so there are commonalities other transportation forms such as trucks, ships, and trains. Heck, many airline dispatchers I've worked with started out dispatching trucks.
Lots of guys and gals I work with are electricians, plumbers, HVAC technicians, or work part time in IT to keep their skills up. I work with two guys who are doing their law degrees, a few of us have business or general science degrees that could quickly morph into some form of masters program, and we have two who are actively using their doctorates for research. Who else...two I know of have a construction and high-end remodelling businesses, another owns a restaurant, yet another owns a bakery with her husband, two who own flight schools, a university professor, a guy I used to work with was a substitute teacher. Then there are the pilots who are real estate agents, a mortician (I've not flown with, he's at another company), a few who do insurance sales. Pretty much, you name the industry and there is a pilot somewhere who has skills or a job in another industry.