Anti-Gravity Tech In Gundam?

So most Gundam Timelines are more-or-less Hard Sci-Fi universes and so should lack things like anti-grav tech. But I help but think that in some of them they have it.

Probably the biggest offender is all the flying base ships, like the White Base and Archangel, seriously how are they supposed to be able to fly, or even worse, hover in place?

Another one is is Mobile Suits able to hover above the ground, they can seemingly, somehow, follow a strict height above terrain flight path, despite sometimes not even having wings!