Perhaps they built Aurora back in the 1980s but I'm pretty skeptical that it still exists (if it ever did). The military utility of a superfast plane is relatively limited compared to the ability to loiter (preferably undetected via stealth) for hours at a time. The work done by UAVs like the Predator and Global Hawk have been invaluable. Loiter ability allows you to follow suspects back to where they're hiding. Loiter ability of ground surveillance aircraft like JSTARS has allowed operaters in the field to trace vehicle movement backwards from things like IED explosions. You observe vehicle movements over a broad area and then run the data backwards once an explosion happens to see what stopped at the explosion site, then trace that vehicle back to where the bomb was prepared. They've done this many times in Iraq. You can't do that kind of analysis by blasting by at Mach 3+.

Even smaller UAVs are being developed and used by smaller combat units down to the company and perhaps platoon level. Back during the Battle for Falluja (sp), I saw a news report on how a small Marine unit used a UAV to locate and take out a group firing a mortar at our guys. Once they found the mortar, they were able to get a high precision target coordinate and take it out.