Are bronchioles and alveoli covered by respiratory epithelium?
From the nose to the pharynx and larynx: stratified squamous epithelium

From the end of larynx to the bronchi: pseudostratified columnar ciliated epithelial cells.

From the small bronchi cartilage is being replaced by elastic tissue.

Bronchioles: ciliated simple epithelium with club cells (known as Clara cells). Also they lack cartilage and glands.

Alveoli are covered with squamous alveolar cells which form the wall (also known as type I pneumocytes). They also contain great alveolar cells (which produce surfactant) or type II pneumocytes and macrophages.

From http://en.wikipedia.org/wiki/Respiratory_tract , http://en.wikipedia.org/wiki/Pulmonary_alveolus and http://en.wikipedia.org/wiki/Pharynx