Air Travel in SA
There are a limited number of airlines operating within SA. SAA and BA/Comair are the 2 main ones, and then there smaller ones such as SAAirlink, SAXpress, and such Airlines as Nationwide!
Your best bet is to go through SAA or BA, as their services are more frequent and carry better reputations!
One word of advice, try and book your ticket as far in advanced as possible, as you pay quite a sustantial amount less than you normally would!