If we were to assume that unidentified flying objects (UFOs) are real and capable of interstellar travel, it would indeed raise questions regarding the applicability of Einstein's theories to their mode of transportation. According to Einstein's theory of relativity, the speed of light is an absolute limit, and objects with mass cannot exceed or reach the speed of light.
However, it's important to note that the existence and capabilities of such hypothetical UFOs are purely speculative at this point, and there is no scientific consensus or conclusive evidence to support the notion of extraterrestrial visitation. That being said, if advanced extraterrestrial civilizations were capable of traversing vast interstellar distances, they would likely require technology or principles that are beyond our current understanding.
There are theoretical concepts such as wormholes, which are shortcuts through space-time, and warp drives, which would enable faster-than-light travel, that have been proposed in science fiction and certain scientific discussions. These ideas involve manipulating the fabric of space-time itself to achieve faster-than-light travel or circumvent the limitations imposed by Einstein's theories. However, it is important to emphasize that these concepts remain purely speculative and speculative at this point.
If UFOs were to exist and be engaged in interstellar travel, it would likely involve scientific principles and technologies far beyond our current understanding. Exploring such possibilities would require advancements in our knowledge of physics and our understanding of the universe.