Airmail pilot E. Hamilton Lee (Smithsonian Institution) Tags: smithsonianinstitution dehavilland airmail usps dehavillanddh4b dh4 dh4b aviation aircraft airplane unitedairlinesflyingest man world helpedestablishworldsfirstschdculedairtransportsystem aviator ehamiltonlee hamiltonlee lee nationalpostalmuseum mailacrossthecommons ehlee usairmail usmail