Lockheed Martin’s CEO was quoted as saying at the company’s media day that the aerospace giant is “now producing a controllable, low-drag, aerodynamic configuration capable of stable operations from takeoff to subsonic, transonic, supersonic and hypersonic, to Mach 6.”
By Source (WP:NFCC#4), Fair use, https://en.wikipedia.org/w/index.php?curid=43517592
Three ideas are being pursued by the company. Firstly the Hypersonic Air-breathing Weapon Concept (HAWC); the Tactical Boost Glide vehicle and a third concept similar to the HAWC but comes with a “turbine-based combined cycle” engine.