The mission was the result of planning that began during World War I, when Allied shipping was threatened by submarine warfare. Designs were started for an airplane capable of flying from the United States to Europe on its own power.
The planes were not finished and tested until after the war was over. The US Navy decided to try a demonstration of trans-Atlantic flight none the less.
The flight began on 8 May. The NC-4 was originally in the company of two other large flying boats, the NC-1 and the NC-3. The planes were made for the Navy by the Curtiss Aeroplane and Motor Company. They left Long Island, New York, then stopped in Newfoundland before leaving on 16 May for the longest leg of their journey, the flight to the Azores, reached 15 hours later. The NC-1 and the NC-3 were both forced to land at sea due to rough weather; the crews were rescued by ships. After delays for repairs, the NC-4 took off again and landed in Lisbon, Portugal on 27 May, becoming the first airplane to cross the ocean under its own power, with 26 hours total flying time. The NC-4 later flew on to London, England.
The crew of the NC-4 was Albert C Read, commander/navigator; Walter Hinton and Elmer F Stone, pilots, James L Breese and Eugene S Rhoads, flight engineers, and Herbert C Rodd, radio operator.
The NC-4 is now preserved in the Naval Aviation Museum in Pensacola, Florida.