The first true aircraft carrier, HMS Furious, was converted from a battlecruiser into a flush-deck aircraft carrier in 1917, and it was the prototype of all flat-tops.
The first aircraft carriers designed from scratch were HMS Hermes and IJN Hosho, which both were launched in 1920. HMS Furious is the only aircraft carrier which did combat operations in both World Wars. She was scrapped in 1948.
