Today, we cannot produce machines that fly the same as UFOs do. They are flying by means of artificial fields of Gravity. This would explain the sudden changes of directions. This hypothesis would also explain the piling-up of these discs into a cylindrical or cigar-shaped mothership upon leaving the Earth.
Hermann OberthThe rockets... can be built so powerfully that they could be capable of carrying a man aloft.
Hermann OberthIt is my conclusion that UFOs do exist, are very real, and are spaceships from another or more than one solar system. They are possibly manned by intelligent observers who are members of a race carrying out long-range scientific investigations of our earth for centuries.
Hermann OberthDespite the immense distance between our own solar system (including the earth) and the nearest other solar systems, a journey from one system to another is theoretically possible, once an unlimited source of power is developed.
Hermann Oberth