The Hughes H-4 Hercules is a prototype strategic airlift flying boat designed and built by the Hughes Aircraft Company. Intended as a transatlantic flight transport for use during World War II, it was not completed in time to be used in the war. The aircraft made only one brief flight, on November 2, 1947, and the project never advanced beyond the single example produced.

The Hughes Aircraft Company was a major American aerospace and defense contractor founded on February 14, 1934 by Howard Hughes in Glendale, California, as a division of Hughes Tool Company. The company produced the Hughes H-4 Hercules aircraft, the atmospheric entry probe carried by the Galileo spacecraft, and the AIM-4 Falcon guided missile.