Those pictures are a hoax!! They have been around for a while on U.S sites. Take a look
http://images.google.co.uk/imgres?imgurl=http://www.spyflight.co.uk/images/JPGS%255CFuture%255Cwedgecrop01.jpg&imgrefurl=http://www.spyflight.co.uk/The%2520Future.htm&h=185&w=300&sz=8&hl=en&start=6&tbnid=RYEi4YO7dZuSQM:&tbnh=72&tbnw=116&prev=/images%3Fq%3Dfake%2Baurora%2Bpictures%26svnum%3D10%26hl%3Den%26lr%3D%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-GB:official_s%26sa%3DG
It could be very true that the U.S has built something very loud and very fast, but this is probably not related to the Aurora myth at all. Way too much money went into the U.S national space plane program though :confused:
When you really wan’t to believe something is real, when theres so much being written and published about Aurora, it almost seems real!
The U.S is very keen to build a hypersonic space reusable craft. Take a look at lockheeds site to see the phase two of the Falcon Small Launch Vehicle (SLV) program. Nov 2003, DARPA and the USAF released contracts to start development for their FALCON program, which is an acronym for Force Application and Launch from CONtinental United States.
It is to be developed in two parts with the SLV expected to be complete by 2010 and a HCV expected by 2025. Nine contractors were initially selected to perform a phase one level systems definition for the SLV.


You could find pictures of the hybrid rocket engine tests until recently but not anymore! The only picture of Lockheeds Falcon on its site is on this page, just like my picture I adapted too! Enjoy.
http://www.lockheedmartin.com/wms/findPage.do?dsp=fec&ci=16505&rsbci=0&fti=0&ti=0&sc=400