UFOs have no obvious form of propulsion because they are not actually moving?

With all the talk over the decades of UFOs possibly using some kind anti gravity device, and the ongoing reverse engineering programs, it seems odd to me that we have now seen the jellyfish UFO, which doesn’t seem to have any “shell” or container, seemingly also defying gravity.

If flying saucers have a large part of their hull taken up by anti-gravity devices along the lines of Bob Lazaars explanation, where is the room for this in the jellyfish UFO or small orbs for instance?

Is it possible that the crafts are from another dimension, and the reason they can exhibit incredible manoeuvres that would turn their pilots to jelly, is because in their dimension they are not moving at all? Are they manipulating our dimension like we turn pages in a book? This may explain why the jellyfish UFO moves in such a linear way and the whole object is so stiff. it may just be sitting in a hangar and never leaves.