The U.S. Navy’s expensive effort to install hypersonic missiles on three Zumwalt-class destroyers is two years behind schedule.

The U.S. Navy’s expensive effort to install hypersonic missiles on three Zumwalt-class destroyers is two years behind schedule.

The GAO determined that the Navy is already roughly two years behind schedule on modernizing the Zumwalt-class destroyers as part of the more than $50 billion hypersonic effort.