Comparative structural‐dynamic characterization of the biopolyester blends based on poly(3‐hydroxybutyrate) and poly‐L‐lactide (PLA) [PHB/PLA] is performed. The melt electrospun fibers and molded films with the same compositions (1/0, 1/9, 3/7) but obtained by two different fabrication ways are explored by combination of structural and dynamic methods. The structural‐dynamic features such as segmental mobility (by spin‐probe ESR technique), thermophysical transitions (by DSC), and surface morphology (by SEM) are applied to elucidate the distinctive diffusion features as the essential constituent of drug release. The ultrathin electrospun fibers and molded films loaded by dipyridamole (DPD), as a modeling drug, shows the different structural behavior including crystallinity and the diversity in diffusion coefficients and the drug release profiles. To emphasize the special transport phenomena in nano‐sized drug vehicles, the diffusivity modeling is performed and further the drug diffusion coefficients in the ultrathin fibers and the macroscopic films are compared.