The story takes place in our future, during the 25th century. I'm looking for a scalable technology that could allow something as small as a cyborg or personal vehicle to fly, or something as big as a massive spaceship to land on Earth safely. While a lot of the technology in this story is fairly realistic, I am prepared to use as much handwavium as required for this particular technology ; all I require is for it to be internally consistent.
The idea is that this technology would allow the user to manipulate gravity around them in order to "pull" them into the sky or the direction they want to move, or to make them light enough to land delicately. The technology is widely spread in society, so it can't be something too difficult and costly to produce in large quantities.
Since current scientific knowledge offers no way to do this (as far as I could find), I'm thinking about introducing undiscovered materials or forces that could be used, or maybe harnessing the effects of dark energy and dark matter in a useable way. As an example, I quite like the "Element zero" idea from the Mass Effect games (a new element which can increase or decrease gravity when it is subjected to an electrical current).
This is my first post here, I hope the question is appropriate.
EDIT : If it's not possible to justify movement with gravity fields alone, it's possible that the technology would only lower the mass of its vehicle enough that low power thrusters would produce movement. The question of how gravity could be manipulated in such a way remains.