We have studied the carrier transport properties of the two series of smectic mesophases. from SmA to SmE phases, and from SmC to SmG phases in 2-pahenynaphthalene and terthiophene derivatives by time of flight measurements, We examine the experimental data with the hopping transport formalism as a function of the molecular distance with the reference to that from X-ray diffraction. We propose another aspect of the carrier transport characteristics as a probe for elucidating the molecular alignment in the smectic layer.