In many respiratory diseases characterized by an intense inflammatory response, the balance between proteolytic enzymes (proteases, including elastases) and their inhibitors (proteinases inhibitors) is not neutral. Excess activity of neutrophil elastase (NE) and similar proteases has been reported to cause tissue damage and to alter the remodeling process in many clinical conditions such as pneumonia, respiratory distress, and acute lung injury (ALI). Several experimental NE inhibitors have been tested in preclinical and clinical studies of different conditions of inflammatory lung injury such as ALI and pneumonia, with contrasting results. This study reviews the literature regarding NE inhibitors in the field of respiratory diseases and reflects on possible future developments. In particular, we highlight potential gaps in the scientific evidence and discuss potential strategies for focusing investigation on antielastases in clinical practice through the selection of targeted populations and proper outcomes.