I'm going to be flying to Africa a fair amount in the next year with my work, probably once a month or so on average. Ghana, Ivory Coast, Togo, DRC, South Africa, etc. With a little bit of Europe and South America (Peru and Bolivia especially) thrown in.

I'm based out of BWI, but if it means I get there/back to my family faster, I can fly out of IAD or DCA. And sometimes out of the NYC airports.

Any suggestions for which airlines or frequent flyer programs to focus on? I'm going to generally be buying the cheapest tickets, but have some wiggle room for shorter flights/fewer connections.