Space Time manipulation is beyond our imagination since we think of space in terms of being 3D but we think of time as a linear single dimension.
Why can't time have 3 dimenions as well. Past, present and future come to mind but I am thinking of a simultaneous 3D quality of time.
No not a time machine per se but nudging space and time to a limited degree so that the UAP's can appear to do impossible movements unrelated to propulsion or areodynamics.