Amazing what people can come up with. Never heard that one before.
But for this to be true, the north polar region would have to be the opposite "edge", and that would mean all those airliners on polar routes would just fly off into space! How would he explain that away? And if the Earth is flat, how does he explain "great circle navigation", which is the reason they use those polar routes? Why have all the ships and airlines always used that form of navigation, which on a round globe saves mileage and fuel by traveling in a curved line but on a flat surface would add mileage and waste fuel? Are all the world's shipping and airline transportation companies part of a global conspiracy to falsely prove the earth is round? and they are dedicated enough to it to waste billions of dollars in wasted fuel and miles of wear on their expensive equipment?
And all those expeditions to both poles? Those people all made it up too? Otherwise, wouldn't they have reported standing on the edge and looking off into space?
These people are entertaining at least.