There's no such thing as a free lunch !
So what will the yanks get out of the deal ?
Compared to the rest of africa, Southern Africa's air traffic controll situation is relatively good , surley the hard earned tax payers of america's money would be better spent on sorting out the abysmal atc situation in central, east and west africa ( pleeeeze Lagos / Kinshasa / Luanda) if they're going to be throwing money all over the place, unless of course there are ulterior motives for choosing southern africa, which these days cant be ruled out- new world order, big brother watching you, have to keep an eye on the natives you know, etc etc.
Cant say I'm too enthusiastic to have a whole lot of americans meddling around in our airspace affairs.
" Slowly slowly catchee monkey !! "