Despite their primitive nature and limited use, these vessels demonstrated the potential of extending airpower into the sea; thus dramatically increasing the flexibility and range of naval power.

By the end of the Second World War, the aircraft carrier had come into its own - moving from its former auxiliary role to become the core of the modern battle fleet and the new measure of naval strength.

While the Royal Canadian Navy had never operated an aircraft carrier during combat, Canadian sailors did man the Royal Navy escort carriers HMS Nabob and Willapa during the Battle of the Atlantic. The dream of a Canadian naval air arm took hold during the war and immediately afterwards the RCN moved to acquire carriers of its own.

Since the sixteenth century, war at sea had been defined by the gun duels of opposing fleets. From the ships of the line which fought at Trafalgar to the mighty dreadnoughts of the First World War; for nearly four centuries maritime power was measured by the size and number of guns a navy could bring to bear. This measure of strength was to undergo a fundamental shift with the advent of the aircraft carrier and naval aviation.

In 1939 the British went to war with 6 fleet carriers. The United States and the Japanese had slightly more developed carrier programs while the French had only one flattop; and France’s early exit from the war prevented its employment. Both the Germans and the Italians sought to acquire carriers of their own throughout the war. However their resources were limited. The Italians were never able to bring their plans to fruition while the one German vessel which was built, the Graf Zeppelin, was never completed and never saw action.

However in 1939 the measure of naval strength around the world still remained the big-gun battleship. The pride of the Royal Navy was still the 14 inch guns of the new King George V class battleships while in the Pacific the Japanese were pouring resources into the construction of two new super battleships.

Yet, the value of aircraft carriers and the vulnerability of the old capitol ships soon became apparent. The attack on Pearl Harbor demonstrated how devastating carrier strikes could be against ships which lacked proper air cover. The Japanese surprise assault on the U.S. naval base sunk or damaged 21 vessels of the Pacific Fleet, including eight battleships.

Pearl Harbor was not the first such demonstration. That attack was modeled on a similar British strike of a year earlier. In November 1940 torpedo bombers from the HMS Illustrious had launched a night-time raid on the main Italian naval base at Taranto. Even the obsolete Swordfish biplanes were able to torpedo three battleships and cripple the Italian fleet for six months.

Throughout the war, carrier aircraft proved again and again that they were the new masters of the ocean. In May 1941 aircraft from the HMS Ark Royal and Victorious helped sink the German battleship Bismarck. Seven months later the British battleships Repulse and Prince of Wales were sunk by Japanese aircraft; and in 1945 the largest battleships ever constructed, the Japanese Yamato and Musashi were killed by U.S. dive bombers and torpedo bombers.

Indeed, the era of gun duels had decisively ended as all the most important naval battles of the Second World War were fought by opposing carrier battle fleets. The Battle of the Coral Sea, fought in the waters southwest of the Solomon Islands in May 1942, was the first ever fleet action in which the two opposing navies could not see one another.

The Coral Sea was largely a draw; however the battle of Midway, which took place north of the Midway Atoll one month later, was not. At Midway, three U.S. carriers sunk four Japanese flattops for the loss of only one of their own number. The loss of only these four ships severely limited the Japanese Navy’s striking power and marked the end of their advance in the Pacific.

In the Atlantic there were fewer such actions, largely because the Germans lacked a large surface fleet while the Italians were loath to risk their capital ships against British air and sea power. However the smaller escort carriers played a vital role in the Battle of the Atlantic. Between June 1941 and April 1945, the United States alone would build and launch 78 escort carriers.

These vessels, teamed with destroyers and frigates, extended Allied power over the Atlantic where shore based planes could not reach. The carriers were also at the center of hunter-killer squadrons which were highly effective at tracking down and destroying German U-boats surfaced in the Atlantic. These versatile ships also served to shuttle planes across oceans and to resupply outposts, freeing their larger cousins up for combat duty.

By 1945 nearly every major fleet was based around aircraft carriers. The United States ended the war with 119 fleet and escort carriers, having lost 11 to enemy action. Great Britain finished the war with 58, having lost 10. While the Royal Canadian Navy had never operated an aircraft carrier during combat, Canadian sailors did man the Royal Navy escort carriers HMS Nabob and Willapa during the Battle of the Atlantic.

With Canadian naval resources focused on keeping the Atlantic sea lanes open, there was little to spare on acquiring that capability for Canada. However, the dream of a Canadian naval air arm took hold during the war and immediately afterwards the RCN moved to acquire carriers of its own. From 1946 to 1948 Canada operated the HMCS Warrior. Yet, designed for the Indian Ocean, its lack of heaters made the ship inadequate for the North Atlantic. It was replaced by the HMCS Magnificent, which served in the Canadian Navy for twelve years until 1956.

By 1957 the Magnificent itself was replaced by the HMCS Bonaventure which was to be the last Canadian carrier. Decommissioned in 1970, the Bonaventure had helped to make the Canadian Navy one of the most capable in the world. It was able to maintain constant air operations and was one of Canada’s only ice-strengthened vessels, eventually becoming the first such warship to make a cruise into the Canadian Arctic.

From the dawn of the Second World War to the present day, the aircraft carrier has been and remains the premier means of maintaining control of the seas and projecting power to foreign shores. From the great battles of the Pacific to its simple but imperative convoy duties, Allied aircraft carriers contributed inestimably to the Allied victories of the Second World War in every naval theatre around the world.