Official data on this does not include "black projects" such as the ever elusive and oft denied Aurora -
So Officially?
The Lockheed SR-71 Blackbird, first flown in 1963, is the fastest operational aircraft to fly within earth's atmosphere. At an operational altitude
of 80,000 feet the SR-71 can achieve speeds over 2,200 MPH or above Mach 3. The airframe is built almost exclusively of titanium to withstand the
extreme heat generated and two Pratt and Whitney J-58 axial flow turbojets producing a total of 68,000 pounds of thrust. Only the experimental X-15
surpasses the SR-71 for the outright records at Mach 6.72.





Just let the military do it's job and let us skeptics wonder.
I wish I coulda been there. (In the airplane of course.)