[aerohead]

The 'flywheel-effect' of the spinning induced magnet spheroid prevents it from 'flipping over' and attaching to the 'suspending' magnet ( as a rifled projectile is prevented from 'wobbling' during it's trajectory ) [ the explanation is hiding in plain view ].
The magnetic flux magnitude determines the separation distance between the two magnets.
Earth's lines of magnetic flux are too feeble to ever allow an aircraft to levitate, even at ground level.
The inverse-square law takes care of the rest.