Earth is not flat because it is a planet and by definition it has enough mass to achieve hydrostatic equilibrium meaning that it is symmetrically rounded into a spheroid or ellipsoid shape. I will not bother to explain further because it is easy for anyone to find out the physics concerning that but what I want to say is that such theories and the organizations behind them who blatantly oppose the obvious, who defy what is scientifically proven , surely they have something to gain moneywise...