Fluid dynamics is only a part of an aerospace degree, I'm not sure studying materials science, control systems, or air traffic rules would help much in writing a CFD program. A couple of courses in fluid dynamics, one in thermodynamics, and a course like this would get you started: http://www.nptelvideos.in/2012/11/foundation-of-scientific-c...

Engineering Mathematics I and II (Stroud) are really nice self-study books.