Yeah, these kind of claims have been made for years. Same with perpetual motion machines.
My hunch as that eventually we will see an anti-gravity device of some kind. Legitimate physicists have been theorizing about it for a long time.
Here's one interesting example.
Pretty much all the claims so far have been in defiance of the laws of physics but one day perhaps someone will come up with a device that uses those laws.
Of course, there are rumors that DARPA has been working on anti-gravity and has even perfected it but if that turns out to be true we won't get to know about it for a long time.
They have in fact been
researching the Casmir Effect, which has certain potential relationships with a possible anti-gravity device, so who knows?