This would make sense if they're counting Operations Research as a type of Mathematician. Those are the people who design the algorithms (not necessarily write the code) for air flight planning, supply-network chains, personnel scheduling, and most forms of resource allocation. Lots of applications in resource extraction, manufacturing, transportation, military, and infrastructure design.

This assumes that they're talking about "Mathematician" as a career, and not just what you can expect with a Math major. If you have a degree in math, you can get quite a high-paying job in a broad range of other industries (like programming and finance, also on the list) because people will just assume you're the smartest person they've ever met.