Ballistic transport refers to the transport of electrons in a medium in which the electrons are not dispersed in it.This occurs when the average free path of the electrons is much greater than the length delimiting the medium, in the direction in which the electron is propagated.
Then this medium does not oppose "resistance" to the passage of the electron, however, the conductivity is not infinite because in an experimental arrangement the medium is connected to the measuring equipment through contacts and therefore a resistance because of them. It is important to establish that superconductivity and ballistic transport are two different phenomena, in the case of ballistic transport if the motive force that the electrons move from one electrode or contact to the other is removed, electrons would stop moving through the medium; while in a superconductor the current would continue to flow even in the absence of this motive force once a current has been established.
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