According to the head of U.S. Air Force Research Laboratory, Maj. Gen. Thomas Masiello, the service will likely have prototype hypersonic missiles by 2020 that can eventually be deployed for operations.
By US Air Force [Public domain], via Wikimedia Commons
Although flight testing of the hypersonic X-51 ended in 2013, the service is still developing engines that could travel at or above Mach 5.