The Defense Department is exploring a potential new ultra-fast, air-launched cruise missile -- specifically a naval variant of the Hypersonic Air-breathing Weapon Concept -- a joint Defense Advanced Research Projects Agency and Air Force effort slated to produce a flying prototype in fiscal year 2019. DARPA Director Steven Walker revealed DOD plans for this notional new Navy hypersonic program on March 1, during a meeting with reporters organized by the Defense Writers Group, where he outlined work the agency is...