Naval combat underwent a significant metamorphosis during World War II. Nazi Germany and Imperial Japan launched some of the most powerful battleships ever to sail the world's oceans, yet the conflict witnessed the emergence and triumph of the aircraft carrier as the 20th century's true monarch of the seas. Submarine warfare expanded and developed, while aircraft technology and doctrine experienced several revolutionary changes due to the unforgiving demands of the new combat environment.

In time, the American and British navies progressively destroyed their Axis counterparts, ensuring clear sea lanes, high strategic mobility for seaborne invasions, and large-scale air support that eventually battered the Axis armies into submission. Just as the Luftwaffe paralyzed Poland's defenders in 1939 with air superiority, so the Allies' mastery of naval and aerial warfare turned the tables to paralyze the Nazis and Japanese: “The fate of Germany and Japan was sealed by the many-layered application of Anglo-American air and sea power. The totality of this pressure [...] eventually choked off Axis mobility. Air and sea power could operate throughout the productive process, not only to affect the battlefield, but to determine how much and what kinds of military equipment were produced and deployed.” (O'Brien, 2015, 480).

Indeed, the “ultimate weapon” of World War II proved to be not a powerful tank or a specific type of aircraft, but a gigantic piece of military hardware combining the newly augmented power of both air and naval operations, the aircraft carrier. Every diverse element of the military machine had a crucial role to play, but the aircraft carrier stood head and shoulders above any other single system as the key to victory in the mid 1940s.