Consider the bottom section of the UFO as an enclosed circular cavity wherein the energy fields can be developed into fields of high permittivity.

The group velocities of the electromagnetic waves will consequently be slowed down. A packet of such electromagnetic waves when ejected tangentially out of that cavity will be a stretched wave-packet. When it leaves the rim and rounds the upper dome shell that stretched wave-packet begins to compress as it curls around the dome through smaller curvature toward the dome's apex. Magnetic pads situated around the apex by working on both the radial element of the electromagnetic wave-packet and on the craft's magnetic flux lines will allow the craft's flux lines to form into a collimated helical filament-tube with pre-designated pitch-angle and bore. The wave-packets curling round the dome can then curl round the apex and into that collimated filament-tube, and be accelerated ahead of the craft along that pre-designated trajectory.

The geometry of the upper dome and the inhomogeneity of the craft's flux lines will work in concert with the geometry of the filament-tube to compress the envelope of that wave-packet in a way analogous to a chirped circularly-polarized field. Back-scatter could also be envisioned to act as an additional compressive mechanism to further amplify the amplitude of that moving field. Either way, the much amplified wave-packet will be sent ahead of the craft.

The result of this action will of course be fully dependent upon what other forces are configured into the electromagnetic wave-packets and too their repetition rate. It will be sufficient to say here that if these factors are dialed-in correctly the wave-packets will become the most intense fields of energy (of that particular kind of force-energy) in the immediate vicinity of that craft, succinctly more intense than when they left the craft's rim as a lowly stretched pulse. So therefore that craft would have no choice but to be dragged in whatever direction those compressed and intensified lambda wave-packets were sent.

Travel in space would be straightforward as the craft would be buoyant and would have no gravitational weight. But so too would it be straightforward in earth's atmosphere if enclosed within the craft there were means by which a horizontal gravitational center were in operation providing a more powerful attraction than earth's vertical gravitational field.

Conveniently, the same mechanism which generates the horizontal gravitational field will also trap any sound waves and so the whole drive-system would run in perfect silence...

Short list-bibliography of research works consulted
 

SOURCE