Which ships were converted from battle cruisers to aircraft carriers during construction?

The USS Lexington and USS Saratoga are notable examples of ships that were originally designed as battle cruisers but were converted to aircraft carriers during their construction. This transformation was part of a strategic shift in naval warfare that recognized the growing importance of air power at sea.

Both vessels were laid down as battle cruisers but, in light of lessons learned from World War I and evolving military needs, the U.S. Navy decided to adapt these ships for carrier operations. This decision to convert them allowed for the inclusion of flight decks and hangar facilities, enabling them to launch and recover aircraft effectively. The conversion process reflected a broader trend in naval design, emphasizing the significance of carriers as key elements of naval strategy in the years leading up to World War II.

In contrast, the other choices consist of ships that either did not undergo such conversion or were of different classes altogether, highlighting the specific historical moment that led to the conversion of Lexington and Saratoga.