Why the G3 battlecruisers were not converted into carriers

Were there plans to convert the G3 battlecruisers, and how might they have compared with Lexington and Saratoga?

No practical G3 conversions were available because construction had barely begun; the more advanced Admiral-class hulls were the missed British opportunity.

The G3 battlecruisers were not far enough along in construction to offer practical carrier conversions. Courageous and Glorious, by contrast, already existed as completed hulls when the treaty choices arrived. Scrapping the unfinished Admiral-class ships before negotiations removed both a possible conversion and a bargaining asset. The episode shows how construction status and premature disposal narrowed the carrier designs available under the Washington settlement.