CG-21
A 21st century air defense cruiser (CG-21) was announced in January 2000 to replace the 27 Ticonderoga class cruisers. Procurement was to begin after the end of the DD-21 program, perhaps around 2015. Development work had not started before the program was terminated in November 2001; CG-21 was replaced by the CG(X) program, which was subsequently cancelled in 2010.
Read more about this topic: SC-21 (United States)