Unsinkable aircraft carrier

An unsinkable aircraft carrier is a term sometimes used to refer to a geographical or political island that is used to extend the power projection of a military force. Because such an entity is capable of acting as an airbase and is a physical landmass not easily destroyed, it is, in effect, an immobile aircraft carrier that cannot be sunk and cannot be moved.

The term unsinkable aircraft carrier first arose during World War II, to describe the islands and atolls in the Pacific Ocean which became strategically important as potential airstrips for American bombers in their transoceanic war against Japan. To this end, the US military engaged in numerous island hopping operations to oust the occupying Japanese forces from such islands; afterwards the US Navy  Seabees would often have to construct airstrips there from scratch — sometimes over entire atolls — quickly, in order to support the air operations against Japan.

Malta was sometimes described as an unsinkable aircraft carrier during World War II, making it a target of the Axis powers. The US military is said to have considered Taiwan since the Chinese Civil War, and the British Isles and Japan during the Cold War, as unsinkable aircraft carriers. In 1983, Japanese Prime Minister Yasuhiro Nakasone pledged to make Japan an "unsinkable aircraft carrier in the  Pacific", assisting the US in defending against the threat of Soviet bombers.

During the Second World War Britain gave some consideration to building virtually unsinkable aircraft carriers from ice reinforced with sawdust (Project Habakkuk). A model was made, and serious consideration was given to the project, with a design displacing 2.2 million tons and accommodating 150 twin-engined bombers being considered, but it was never produced.