Which carrier is recognized as the first designed from the keel up?

The first aircraft carrier designed from the keel up is the CV-4 USS Ranger. This ship was notable for being the first carrier built specifically as an aircraft carrier rather than being converted from an existing vessel. Established in the 1930s, the Ranger had a different focus on design elements, flight deck features, and capabilities that allowed it to operate more effectively as an aircraft carrier from its inception.

Recognizing its role as a pioneering design in naval architecture, the USS Ranger set the standard for future carriers, influencing both construction methods and operational strategies. The other carriers, while also significant, either began as different types of ships or underwent significant conversions from their original designs, highlighting the unique historical importance of the Ranger in aviation and naval combat history.