 Any debate over converting them was quelled by the signing of the Washington Naval Treaty . Under the terms of the treaty , any capital ships that were under construction by the five signatories ( the United States , Great Britain , France , Italy and Japan ) had to be canceled and scrapped . For battlecruisers , this encompassed the United States ' Lexington class , Japan 's Amagi class , and Great Britain 's G3 battlecruisers . However , the treaty did allow the participating nations to take two of the capital ships they had under construction and convert them to aircraft carriers ; the U.S. Navy decided to complete the two Lexingtons that were closest to completion , Lexington and Saratoga . 
