Pulmonary inflammatory diseases such as asthma, chronic obstructive pulmonary disease, acute respiratory distress syndrome, idiopathic pulmonary fibrosis, and infection-driven lung inflammation impose a large clinical burden, yet the therapeutic problem is not only inadequate drug potency but also inadequate site-specific exposure in diseased lung compartments. Conventional corticosteroids, bronchodilators, antifibrotics, anti-infectives, and biologics can be effective in selected phenotypes, but their benefits are limited by heterogeneous airway deposition, mucus obstruction, impaired macrophage clearance, systemic toxicity, steroid resistance, and poor adherence. Inhalable nanomedicine is therefore best considered a barrier-driven drug delivery strategy rather than a universally superior therapeutic class. This review critically evaluates whether carrier composition, particle engineering, and inhalation device selection can convert nanoscale advantages into measurable clinical value. Emphasis is placed on quantitative aerosol outputs (mass median aerodynamic diameter, fine-particle fraction, emitted dose, and delivered dose), post-aerosolization nanocarrier integrity, mucus/surfactant interaction, pharmacodynamic superiority over free drug, repeat-dose pulmonary safety, manufacturability, and regulatory readiness. The analysis deliberately distinguishes approved inhaled liposomal precedent from exploratory preclinical systems, because only the former currently provides direct human regulatory evidence. Accordingly, the field is framed as a selective translational opportunity that requires disciplined evidence generation rather than broad claims of near-term clinical implementation.