I have heard about a device that used gravity to pull water down one side of a huge wheel. The energy harnessed from this turning wheel would then be used to grind flour and perform other tasks. I believe more recent versions are human hair wave even able to generate electricity! They call these “hydro-electric” but they really should be called “gravo-electric” because it’s the gravity that does all the work.
As for making things fly, take an airtight sack, fill it with a lighter-than-air gas such as helium, release it, and voila,human hair wave gravity will pull the heavier air down thus forcing your inflated sack fly upwards. Note: the sack can be decorated and used to impress friends at parties.
Don’t confuse gravitational human hair wave with gravitons. The latter are hypothetical particles that would mediate gravitational force and would therefore, if they exist, be continuously exchanged between massive objects. Gravitational waves are emitted only when there is a disturbance.
Unfortunately there is no prospect of human hair wave to make useful amounts of gravity waves or to make things fly. It requires literally astronomical quantities of mass whirling at near-light speed in a tight orbit to make gravitational waves that are barely detectable (and as yet have not been, although stay tuned). And gravity is an intrinsically attractive force, so orbiting and plummeting are the most one can hope for, and these are not new.
But if you mean, when will we have scifi-style antigravity, that’s a whole other question. The trouble is we don’t understand gravity very well. We don’t even know if it exists as a distinct force like electromagnatism. If it does, human hair wave it might one day be possible to build graviton circuitry. If not, then the only way to generate gravity is by warping space with mass, and the only way to create a local concentration of mass is by pumping in quantities of energy that would make the Tsar Bomba look like a birthday cake candle dipped in liquid nitrogen by comparison.