Defect engineering provides an effective means of tuning the charge transport in ferrimagnetic oxides. Here, we present a comparative study of M-type (BaFe12O19, SrFe12O19) and W-type (BaCo2Fe16O27, BaZn2Fe16O27) hexaferrites synthesized via sol-gel auto-combustion. Using XRD, SEM, TEM, dielectric measurements, and current-voltage measurements, lattice defects are linked to charge-carrier conduction pathways. XRD confirmed phase-pure hexagonal structures with nanocrystallite sizes of 33-36 nm. High-resolution TEM revealed edge dislocations and planar strain fields in BaFe12O19, along with stacking-fault arrays in BaCo2Fe16O27, which create localized strain-induced potential fluctuations. The presence of dislocations and oxygen-vacancy defects promotes field-assisted thermionic emission with trap densities of similar to 1016 cm-3 and earlier onset of space-charge-limited conduction. Dielectric spectroscopy revealed Maxwell-Wagner relaxation, while the J-E analysis indicated that Schottky emission dominates, with secondary space-charge-limited conduction occurring at high electric fields. The results demonstrate that oxygen-vacancy and strain-related defects serve as active transport mediators, providing a pathway to tune the electrical properties of ferrites for multifunctional electronic and energy applications.