Here is an example of the flat earth thinking on this topic.
This video in particular by Nina aka "Zetetic Flat Earth" ( Restricted in some countries, If it doesn't come up on YT, it's also on Vimeo at
https://vimeo.com/138874902 )
Start watching at 11:20 since it has specific flight time information is worth looking at further.
The video author has obviously never bought international tickets and doesn't understand the one free stop option. This is where you buy a ticket from Johannesburg to Sao Paulo, and you can nominate a single stop over, which you get to choose from whatever options are available, in this case one of the options is to fly BA and spend a few days in London.
Why not read the lines above where it clearly says SAA offers a direct flight. Or even notice the little inset map, which shows the flight route?
Instead of trying to find out why you would fly to London, the video author with pre-conceived notions in mind starts a train of thought that is just plain stupid, suggesting that this is the round earth way to fly from Johannesburg to Sao Paulo .. WTF?
And then goes on to point out that the flat earth model using the Gleason map, makes more sense.. well no it doesn't just goes to show how stupid the author is.
Here is the real flight path on Google Earth.
And here are the real flight arrival and departure times.
Sao Paulo is UTC-3:00 and Johannesburg is UTC+2:00 , so departs at 9:00PM UTC and arrives 5:25AM the following morning, that's 8 hours 25 minutes flying time.
If I'm being generous I'm guessing the author of the video has made an honest mistake, I can sympathize, but it is so easy to check these sort of facts before going to commit to a video, for that sake of the hundreds of gullible fools who will just accept it as being true and so the misinformation and the lies propagate.