What UFOs could teach about fundamental physics?

Here is my comment about UFOs to Not-Even-Wrong discussion group, where it was mentioned that Michio Kaku, string theorists and author of "Hyper-Space", has expressed publicly as his opinion that UFOs might be a real. Leaving aside ontological considerations and the question what one should think about people taking seriously UFOs, one could take UFOs as an inspiration for a thought experiment. Suppose for a moment that UFOs represent a real technology. According to the reports, UFOs seem to have a very small inertial mass (butterfly like motions involving sudden accelerations and changes of direction of motion without producing any shock waves). A technology able to reduce dramatically inertial mass of a material object would thus exist. What could this tell about fundamental physics? A possible answer would be a modification of Equivalence Principle. Gravitational mass would be absolute value of inertial mass, which can have both signs. One of the most obvious implications is an explanation for why gravitational energy is definitely not conserved in cosmological scales whereas there is no evidence for the non-conservation of inertial energy. The simplest cosmology would be that created from inertial vacuum by energetic vacuum polarizations creating regions of positive and negative density of inertial mass. The 4-D universe replacing itself by a new one quantum jump by quantum jump would become possible and the difficult philosophical problems formulated as questions like "What was the initial state of the Universe and what were the initial values/densities of conserved quantities at the moment of big bang" would disappear. The observations motivating the anthropic principle would find a natural explanation: the universe has gradually quantum engineered itself so that the values of these constants are what they are. Technological implications would be also interesting. Forming an tightly bound state of systems with positive and negative inertial mass a large feather light system could be created. Could UFOs utilize this kind of technology? Accepting negative energies, one cannot avoid the questions whether negative energy signals propagate backwards in (geometric) time and whether phase conjugate light discovered at seventies could be identified as signals of this kind. Positive answer would have quite interesting technological implications. Negative energy signals time reflected as positive energy signals from time mirrors (lasers with population reversal for instance) would allow communications with geometric past. Our memory might be based on this mechanism: to recall memories would be to scan the brain of geometric past by using reflected in time direction (rather than in spatial direction as seeing in the ordinary sense). Communications with the civilizations of the geometric future and past might become possible by a similar mechanism. Matti Pitkanen