The SR-71 “Blackbird” is the fastest aircraft ever built, excepting space flight capable ones. It set the record in 1976, and it has not been broken. Mach 3.3
"Mach 3.3" sounds really impressive, but it doesn’t mean anything tangible. How about this: it AVERAGED a flight time of 67 minutes from LA to DC. Delta will do it in about 6 hours, by comparison. That’s "suck-the-hair-off-your-head" fast.
The Lockheed-Martin SR-71 “Blackbird” was developed at the famed Skunk Works (Lockheed Martin’s Advanced Research and Development Facility).