Cystic fibrosis (CF) is a chronic progressive pulmonary disorder caused by mutations in the CFTR (cystic fibrosis transmembrane conductance regulator) gene. A CF lung is generally characterized by obstructed airflow to an extent that leads to destruction of airway wall support structure. Airway resistance, resulting from both laminar and turbulent flow, is an important mechanical factor contributing to flow of air into and out of the airways. There are numerous research studies focusing on airflow in the respiratory system that assumed flow to be only laminar and steady. The goal of this research is to describe the air flow mathematically by considering the resistance from both laminar and turbulent airflow throughout the entire respiratory tract. Furthermore, we implement a model that includes airway clogging in CF lungs and recalculate the rate of air flow given these obstructions.