Short answers, pulled from the story.
An aircraft carrier is a warship designed to carry, launch, recover, and support aircraft at sea, equipped with a full-length flight deck and hangar facilities that allow it to function as a mobile, seagoing airbase. It typically serves as the capital ship of a fleet, allowing a naval force to project air power far from national territory without depending on local airfields.
Eugene Burton Ely made the first experimental takeoff of an airplane from a warship on the 14th of November 1910, flying a Curtiss Pusher airplane from the deck of a United States Navy cruiser anchored off Norfolk Navy Base in Virginia. Two months later, on the 18th of January 1911, he also completed the first landing of an airplane on a ship, setting down on a platform fitted to an armored cruiser in San Francisco Bay.
The four systems are CATOBAR (catapult-assisted take-off, barrier-arrested recovery), STOBAR (short take-off, barrier-arrested recovery, using a ski-jump ramp), STOVL (short take-off and vertical landing, using thrust-vectoring aircraft), and helicopter carriers that operate only rotary-wing aircraft. CATOBAR allows the heaviest aircraft loads but is the most expensive, while STOVL and ski-jump systems are cheaper but impose payload penalties.
The first carrier-launched airstrike was the Tondern raid in July 1918. Seven Sopwith Camels were launched from a battlecruiser that had been completed as a carrier, and they attacked the German airbase at Tondern, in what is today Tønder, Denmark, destroying two zeppelin airships.
The largest aircraft carrier in service as of 2024 is the USS Gerald R. Ford, with a full-load displacement of around 100,000 tons and a length of 337 meters. It was commissioned in 2017 and is the lead ship of its class, which uses an Electromagnetic Aircraft Launch System rather than traditional steam catapults.
Modern large aircraft carriers require speeds above 30 knots to evade nuclear submarines, and their size and aircraft complement demand enormous power for propulsion, electricity, and catapult systems. Nuclear reactors provide that power without the need to refuel at sea, allowing extended deployments. The combination of high speed requirements and long periods at sea made nuclear propulsion the practical choice for the largest carriers.