Aircraft carrier
The first carrier-launched airstrike was the Tondern raid in July 1918. Seven Sopwith Camels were launched from the battlecruiser HMS Furious which had been completed as a carrier by replacing her planned forward turret with a flight deck and hangar prior to commissioning. The Camels attacked and damaged the German airbase at Tondern, Germany (modern day Tønder, Denmark), and destroyed two zeppelin airships.
The first landing of an airplane on a moving ship was by Squadron Commander Edwin Harris Dunning, when he landed his Sopwith Pup on HMS Furious in Scapa Flow, Orkney on 2 August 1917. Landing on the forward flight deck required the pilot to approach round the ship's superstructure, a difficult and dangerous manoeuver and Dunning was later killed when his airplane was thrown overboard while attempting another landing on Furious. HMS Furious was modified again when her rear turret was removed and another flight deck added over a second hangar for landing aircraft over the stern. Her funnel and superstructure remained intact however and turbulence from the funnel and superstructure was severe enough that only three landing attempts were successful before further attempts were forbidden. This experience prompted the development of vessels with a flush deck and produced the first large fleet ships. In 1918, HMS Argus became the world's first carrier capable of launching and recovering naval aircraft.
As a result of the Washington Naval Treaty of 1922, which limited the construction of new heavy surface combat ships, most early aircraft carriers were conversions of ships that were laid down (or had served) as different ship types: cargo ships, cruisers, battlecruisers, or battleships. These conversions gave rise to the USS Langley in 1922, the US Lexington-class aircraft carriers (1927), Japanese Akagi and Kaga, and British Courageous class (of which Furious was one). Specialist carrier evolution was well underway, with several navies ordering and building warships that were purposefully designed to function as aircraft carriers by the mid-1920s. This resulted in the commissioning of ships such as the Japanese Hōshō (1922), HMS Hermes (1924, although laid down in 1918 before Hōshō), and Béarn (1927). During World War II, these ships would become known as fleet carriers.

World War II: The aircraft carrier dramatically changed naval warfare in World War II, because air power was becoming a significant factor in warfare. The advent of aircraft as focal weapons was driven by the superior range, flexibility, and effectiveness of carrier-launched aircraft. They had greater range and precision than naval guns, making them highly effective. The versatility of the carrier was demonstrated in November 1940, when HMS Illustrious launched a long-range strike on the Italian fleet at their base in Taranto, signalling the beginning of the effective and highly mobile aircraft strikes. This operation in the shallow water harbor incapacitated three of the six anchored battleships at a cost of two torpedo bombers.
World War II in the Pacific Ocean involved clashes between aircraft carrier fleets. The Japanese surprise attack on the American Pacific fleet at Pearl Harbor naval and air bases on Sunday, 7 December 1941, was a clear illustration of the power projection capability afforded by a large force of modern carriers. Concentrating six carriers in a single unit turned naval history about, as no other nation had fielded anything comparable. In the "Doolittle Raid", on 18 April 1942, the US Navy carrier USS Hornet sailed to within 650 nautical miles (1,200 km) of Japan and launched 16 B-25 Mitchell medium bombers from her deck in a demonstrative retaliatory strike on the mainland, including the capital, Tokyo. However, the vulnerability of carriers compared to traditional capital ships was illustrated by the sinking of HMS Glorious by German battleships during the Norwegian campaign in 1940.
This new-found importance of naval aviation forced nations to create a number of carriers, in efforts to provide air superiority cover for every major fleet to ward off enemy aircraft. This extensive usage led to the development and construction of 'light' carriers. Escort aircraft carriers, such as USS Bogue, were sometimes purpose-built but most were converted from merchant ships as a stop-gap measure to provide anti-submarine air support for convoys and amphibious invasions. Following this concept, light aircraft carriers built by the US, such as USS Independence (commissioned in 1943), represented a larger, more "militarized" version of the escort carrier. Although with similar complement to escort carriers, they had the advantage of speed from their converted cruiser hulls. The UK 1942 Design Light Fleet Carrier was designed for building quickly by civilian shipyards and with an expected service life of about 3 years. They served the Royal Navy during the war, and the hull design was chosen for nearly all aircraft carrier equipped navies after the war, until the 1980s. Emergencies also spurred the creation or conversion of highly unconventional aircraft carriers. CAM ships were cargo-carrying merchant ships that could launch (but not retrieve) a single fighter aircraft from a catapult to defend the convoy from long range land-based German aircraft.

Postwar era: Before World War II, international naval treaties of 1922, 1930, and 1936 limited the size of capital ships including carriers. Since World War II, aircraft carrier designs have increased in size to accommodate a steady increase in aircraft size. The large, modern Nimitz class of US Navy carriers has a displacement nearly four times that of the World War II–era USS Enterprise, yet its complement of aircraft is roughly the same—a consequence of the steadily increasing size and weight of individual military aircraft over the years. Today's aircraft carriers are so expensive that some nations which operate them risk significant economic and military impact if a carrier is lost.

Some changes were made after 1945 in carriers:

The angled flight deck was invented by Royal Navy Captain (later Rear Admiral) Dennis Cambell, as naval aviation jets higher speeds required carriers be modified to "fit" their needs. Additionally, the angled flight deck allows for simultaneous launch and recovery.
Jet blast deflectors became necessary to protect aircraft and handlers from jet blast. The first US Navy carriers to be fitted with them were the wooden-decked Essex-class aircraft carriers which were adapted to operate jets in the late 1940s. Later versions had to be water-cooled because of increasing engine power.
Optical landing systems were developed to facilitate the very precise landing angles required by jet aircraft, which have a faster landing speed giving the pilot little time to correct misalignments, or mistakes. The first system was fitted to HMS Illustrious in 1952.
Aircraft carrier designs have increased in size to accommodate continuous increase in aircraft size. The 1950s saw US Navy's commission of "supercarriers", designed to operate naval jets, which offered better performance at the expense of bigger size and demanded more ordnance to be carried on-board (fuel, spare parts, electronics, etc.).
The combination of increased carrier size, speed requirements above 30 knots (35 mph; 56 km/h), and a requirement to operate at sea for long periods mean that modern large aircraft carriers often use nuclear reactors to create power for propulsion, electricity, catapulting airplanes from aircraft carriers, and a few more minor uses.
Modern navies that operate such aircraft carriers treat them as capital ships of fleets, a role previously held by the galleons, ships-of-the-line and battleships. This change took place during World War II in response to air power becoming a significant factor in warfare, driven by the superior range, flexibility and effectiveness of carrier-launched aircraft. Following the war, carrier operations continued to increase in size and importance, and along with, carrier designs also increased in size and ability. Some of these larger carriers, dubbed by the media as "supercarriers", displacing 75,000 tons or greater, have become the pinnacle of carrier development. Some are powered by nuclear reactors and form the core of a fleet designed to operate far from home. Amphibious assault ships, such as the Wasp and Mistral classes, serve the purpose of carrying and landing Marines, and operate a large contingent of helicopters for that purpose. Also known as "commando carriers" or "helicopter carriers", many have the capability to operate VSTOL aircraft.
The threatening role of aircraft carriers has a place in modern asymmetric warfare, like the gunboat diplomacy of the past. Carriers also facilitate quick and precise projections of overwhelming military power into such local and regional conflicts.
Lacking the firepower of other warships, carriers by themselves are considered vulnerable to attack by other ships, aircraft, submarines, or missiles. Therefore, an aircraft carrier is generally accompanied by a number of other ships to provide protection for the relatively unwieldy carrier, to carry supplies, re-supply (Many carriers are self-sufficient and will supply their escorts) and perform other support services, and to provide additional offensive capabilities. The resulting group of ships is often termed a carrier strike group, battle group, carrier group, or carrier battle group.
There is a view among some military pundits  that modern anti-ship weapons systems, such as torpedoes and missiles, or even ballistic missiles with nuclear warheads have made aircraft carriers and carrier groups too vulnerable for modern combat.