The Seamaster Airplane

The U.S. Navy did not have an aircraft carrier that could host an aircraft large enough to carry the first generation nuclear weapons. This is the reasoning for development of this type of aircraft. Water borne planes had existed for years, carrying passengers and cargo to places too small for a runway but were near bodies of water. Look up info on the Pan Am Clipper service that ran from 1931 to 1946.

The Navy also tried to develop the Sea Dart, a water borne fighter during this same time period. I suppose it would have been used for protection of the bombers during an attack mission - they could be based together in some out of the way location while on standby. Unfortunately, one of the Sea Darts disintegrated during a test flight, killing its pilot and the program was cancelled.