The Curtiss Model H was a family of classes of early long-range flying boats, the first two of which were developed directly on commission in the United States in response to the £10,000 prize challenge issued in 1913 by the London newspaper, the Daily Mail, for the first non-stop aerial crossing of the Atlantic.

These changes were produced under contract from Curtiss' factory in the last order of 50 "H-4s", giving a class total of 64, before the evolution of a succession of larger, more adaptable, and more robust H-class models.

This article covers the whole line of nearly 500 Curtiss Model H seaplane flying boat aircraft known to have been produced, since successive models – by whatever sub-model designation – were physically similar, handled similarly, essentially just being increased in size and fitted with larger and improved engines – the advances in internal combustion engine technology in the 1910s being as rapid and explosive as any technological advance has ever been.

When London's Daily Mail newspaper put up a £10,000 prize for the first non-stop aerial crossing of the Atlantic in 1913, American businessman Rodman Wanamaker became determined that the prize should go to an American aircraft and commissioned the Curtiss Aeroplane and Motor Company to design and build an aircraft capable of making the flight.

The class, while commissioned by Wanamaker, was designed under Porte's supervision following his study and rearrangement of the flight plan and built in the Curtiss workshops.

The aircraft resembled Curtiss' earlier flying boat designs, but was considerably larger in order to carry enough fuel to cover 1,100 mi (1,770 km).

Named America[2] and launched 22 June 1914, trials began the following day and soon revealed a serious shortcoming in the design: the tendency for the nose of the aircraft to try to submerge as engine power increased while taxiing on water.

These plans were interrupted by the outbreak of the First World War, which also saw Porte, who was to pilot the America with George Hallett, recalled to service with the British Royal Navy.

Consequently, as the war progressed, the Model H was developed into progressively larger variants, and it served as the basis for parallel developments in the United Kingdom under John Cyril Porte which led to the "Felixstowe" series of flying boats with their better hydrodynamic hull forms, beginning with the Felixstowe F.1 — a hull form which thereafter became the standard in seaplanes of all kinds, just as sponsons did for flying boats.

With the RNAS, H-12s and H-16s operated from flying boat stations on the coast in long-range anti-submarine and anti-Zeppelin patrols over the North Sea.