The NC-4 is a Curtiss NC flying boat that was the first aircraft to fly across the Atlantic Ocean, albeit not non-stop. The NC designation was derived from the collaborative efforts of the Navy (N) and Curtiss (C). The NC series flying boats were designed to meet wartime needs, and after the end of World War I they were sent overseas to validate the design concept.

The Curtiss NC was a flying boat built by Curtiss Aeroplane and Motor Company and used by the United States Navy from 1918 through the early 1920s. Ten of these aircraft were built, the most famous of which is the NC-4, the first airplane to make a transatlantic flight. The NC-4 is preserved in the National Museum of Naval Aviation, at NAS Pensacola, Florida.