I think the shape is due to some sort of plasma https://farm4.staticflickr.com/3914/14712232006_177b385f3e_b.jpg It makes gaseous lights like that around object The point being total isolation of the said object/craft from the fluid/environment it is navigating into, whether water or air So basically there's zero friction/no speed limitation due to friction The TR3B is said to function on a similar principle if memory serves https://en.wikipedia.org/wiki/Black_triangle_(UFO)#TR-3A_Black_Manta MHD propulsion https://en.wikipedia.org/wiki/Magnetohydrodynamic_drive#Principle The working principle involves the acceleration of an electrically conductive fluid (which can be a liquid or an ionized gas called a plasma) by the Lorentz force, resulting from the cross product of an electric current (motion of charge carriers accelerated by an electric field applied between two electrodes) with a perpendicular magnetic field. The Lorentz force accelerates all charged particles (positive and negative species) in the same direction whatever their sign, and the whole fluid is dragged through collisions. As a reaction, the vehicle is put in motion in the opposite direction. This is the same working principle as an electric motor (more exactly a linear motor) except that in an MHD drive, the solid moving rotor is replaced by the fluid acting directly as the propellant. As with all electromagnetic devices, an MHD accelerator is reversible: if the ambient working fluid is moving relatively to the magnetic field, charge separation induces an electric potential difference that can be harnessed with electrodes: the device then acts as a power source with no moving parts, transforming the kinetic energy of the incoming fluid into electricity, called an MHD generator.