Are we just showing off or getting ready for some big fight?

http://en.wikipedia.org/wiki/Waverider

A WaveRider is a hypersonic aircraft design that improves its supersonic lift-to-drag ratio by using the shock waves being generated by its own flight as a lifting surface, a phenomenon known as compression lift. To date the only aircraft to use the technique is the Mach 3 supersonic XB-70 Valkyrie, which was waverider-like with its drooping wingtips. The waverider remains a well-studied design for high-speed aircraft in the Mach 5 and higher hypersonic regime, although no production design has used the concept to date. The Boeing X-51A scramjet demonstration aircraft is in the final stages of development and made its first hypersonic flight in May 2010.[1][2]