Carrier Tactics from 1939-1942: A Steep Learning Curve
Arguably, the design and use of carriers as adjuncts to battleship fleets made them far weaker in the early years of World War II than they could have been. It is also possible that the heavy losses in carriers during the early years of the war, especially by Great Britain, demonstrated that both designers and admirals had seriously misunderstood their potential.
In 1939 the only combatant nation to possess a significant carrier fleet was the United Kingdom. Its fleet was composed largely of one-off designs or converted ships: HMS Hermes and HMS Ark Royal were examples of the former, HMS Argus, HMS Eagle, HMS Furious, HMS Glorious, and HMS Courageous were of the latter group. At the start of the war, only HMS Ark Royal's design had shifted away from that of a ship meant to support battleships to one meant to engage in aerial combat.
The development of the aircraft carrier tactics of World War II began soon after the September, 1939 declaration of war. British carriers were scattered across the seas, broken up into forces composed of a carrier and a battleship or battlecruiser. Several of these forces would often conjoin to conduct operations, but carriers were still effectively slaved to the needs of the rest of the fleet. Due to the relative weakness of the German Navy, this meant that the fleet engaged in North Sea patrols and worked to support the movement of merchant ships between the Allies and their overseas colonies.
This brought British carriers into the fight against the U-Boats and surface raiders of the Kriegsmarine, where they scouted for pocket battleships and U-boats attempting to attack British ships and facilities. In truth, they were rather unsuccessful. U-29 hit Courageous with two torpedoes as she conducted air operations two weeks after the war began and she sank like a stone. Glorious was destroyed when caught at sea during the Norwegian Campaign of 1940 by the German battlecruisers Scharnhorst and Gneisenau. Ark Royal was sunk by U-81 in 1941 after nearly being torpedoed in the past. Eagle was sunk by U-73 in the Mediterranean in 1942, and Hermes was blasted and sunk by Japanese aircraft in the Indian Ocean that same year.