I took an odd path.
I studied engineering, have a BS in aerospace eng and a MS in mechanical eng. I spent some time doing supersonic propulsion research. I published some work in that area, along with general fluid mechanics and heat transfer. I also worked as a design engineer for military aircraft for a while. I ultimately got out of this area because the workers were nomadic. Many of them had to move every 2-3 years to follow the money, basically. Everything was a cycle based upon military spending.
I got into telecom years ago and have stuck with that. For the past few years I've been working as an engineer and project manager for a small consulting firm in Boston. Lately I've been doing some IT related work that kind of ties into telecom.