p.s. After reading Eric Dubay's book, I attempted to book a flight from the tip of South Africa to the tip of South America, I learned that all such flights stop to refuel in Europe or UAE. This makes no sense at all on a globe map, but makes perfect sense on a flat earth map.
A question that occurs to me: are you looking only at
commercial flights?
If so, a commercial airline has to have enough passengers to make the flight profitable. Are there enough people that travel from Johannesburg to Sao Paolo, for example, to make a direct flight viable? Or do they need to fly to a major hub, such as London, in order to have enough passengers to make it pay?
For example: all the commercial flights from my local airport fly to a metro hub. There's a larger town that I drive to semi-regularly about 150 miles away. If I wanted to fly there via commercial airline , I would have to fly to the metro hub (~250 miles), then change planes to fly 160 miles to get to that town. It's simply the economic factors that determine that.
Now if a person hired a charter to fly from Johannesburg to Sao Paulo, and was taken via London,
that would be very compelling.