Magnetic fields can be arranged around other magnetic fields.
Even solutions [fluids] can be magnetized to create clever shaped fields within fields... sometimes at right angles to each other, sometimes not, to give you a condition that will create a change in mass. None of these things are out of the purview of Human
development. How long it'll take? We don't know. That's up to you.
But do you understand what it will change? Everything! It means that the things of science fiction
are finally yours. What you called anti-gravity is simply an object with controllable mass. It'll float no matter how big. It's doable. Maybe it's time to implement it?