They think "grabbity" (or "droppity", lol) is an unproven "pseudoscience", and TRY (unsuccessfully) to replace it with either/both "bouyancy" or "density". Except, in physics, neither bouyancy or density have a direction/"vector"without gravity, and "bouyancy" actually depends on gravity in the formula that defines it.
They have a whole, complex take on formal science, where they claim they're the only people following "real" scientific method, and that scientific fields that are mostly observational, rather than experimental (eg astronomy, seismology, geology) aren't "real science" at all. They borrow heavily from hardcore Young Earth Creationists ("evolution isn't real science, because all you can tell from fossils is that something died") with this stuff, but dial it all up to eleven. Also a fair bit of "zetetic" philosophy, where you can only trust what you personally witness- So 100% of scientific knowledge and precedent is useless.
It's such a bizarre mindset- weirdly fascinating, in a "car crash", "can't look away" kind of way. In terms of conspiracy groups, I never saw another group re-define fundamental reality so thoroughly as these guys, and it really seems to be building steam right now.
I watched the film on Netfix about Flatearthers. I find them harmless enough and each to their own. The only problem I had with he film,is when at a conference ,there was kids there who were believing what these people were telling them. They claimed to disagree with their teachers in school when they were taught that the Earth is a globe.These kids will be marked out as weirdos by their peers because of their parents beliefs. This could also be said of kids in certain religions, but we can prove the Earth is round.The programme also showed that the experiments the Flaearthers tried only reinforced the opposite of their beliefs.
In the flat earth 'model', Antarctica is a real continent as such, but a wall of ice going around the whole world, sort of keeping the water in I suppose. To prevent anyone finding this out, everyone is prevented from going to Antarctica but... someone. And those people who claim to have been there are lying or something. That's nothing compared to the contrived way they explain the sun, which is only a few thousand miles away, and circles above the Earth giving out directional light in their model. Well it has to, of course, or there wouldn't be night time or seasons.