BiL and Flying Saucers.

I have always thought that if flying saucers that can zig-zag
around the sky exist then they are probably using the earth's
magnetic field. That's to say they are lifted and zotted around
by magnetic levitation. ML is nothing new and is used in rapid
transit systems like the Japanese bullet trains. You produce
two oppposing magnetic fields that repel each other. One in
the track and one in the carriage and, whoosh, away you go
fast and frictionless. So to fly in the sky you have the craft's
magnetic field interact with the earth's nature made magnetic
field. Trouble is that the earth's field is so small that the craft's
magnetic field would have to be enormous. We are not yet able
to produce fields of sufficient strength but maybe our visitors
from planet X can.

It comes down to BiL. A conductor of length L meters
carrying a current i Amps in a magnetic field of B tesla
( isnt science great?!) experiences a force F Newtons where

F=BiL Newtons ( 1)    Re-arranging;  i=F/(BL) Amps ( 2 ).

Now, a craft of reasonable mass say 1,000 kilos has a weight
at the earth's surface of 10,000 Newtons ( F=10,000 ). So
if the craft had conductors of total effective length 100
meters ( L=100 ) and we substitute this with the earth's
magnetic field of 5/100,000  Tesla ( B=5/100,000 ) into ( 2 ),
the necessary current to lift the craft free of gravity is

     i=2,000,000 Amps
So, to zot around, our flying saucer would have to
generate and control currents of the order of a million
Amps.  What you get in a lightening bolt. Big potatoes, but with
the advances of superconductor technology, maybe not too far
away. So what?! So for speed freaks; Biggleswade to Surabaya
in two hours. Aerobatics; these machines would make
humming birds look like drunken ducks.