Summary and Key Points: For decades, rumors claimed the U.S. had secretly built the SR-91 Aurora — a hypersonic spy plane flying at Mach 5 to replace the SR-71 Blackbird.
-The legend was fueled by a mysterious 1980s Pentagon budget line, a triangular aircraft spotted over the North Sea, and “sky quakes” over Los Angeles near Area 51.
B-2 Bomber Sitting in Museum National Security Journal Photos. All Rights Reserved.
B-2 Stealth Bomber July 2025 National Security Journal Photo.
-But Skunk Works director Ben Rich wrote that the hypersonic Aurora never existed — the real “Aurora” was the codename for the B-2 Spirit bomber.
SR-91 Aurora: A Total Mystery?
Aviation enthusiasts have been enthralled with the term “hypersonic” for several years, but for the most part, that catchword has been by and large associated with missiles, something that Russia and China claim to have fielded.
Russia also claimed to have fired hypersonic missiles in its invasion of Ukraine.
But hypersonic aircraft (flying at Mach 5, or 3836 mph) is another thing.
Rumors of the United States – and specifically the Lockheed-Martin Skunk Works – of building a hypersonic spy plane to replace the SR-71 Blackbird have been around for decades.
Enter the SR-91 Aurora: The Evidence
A couple of incidents sparked interest in the U.S. hypothetical building in a hypersonic spy plane. In the 1980s, the Pentagon’s budget request had the name “Aurora” beneath the SR-71 and the U2 spy aircraft.
A few years later in August 1989, an oil-exploration engineer named Chris Gibson reported seeing a triangular-shaped aircraft flying over the North Sea following a KC-135 tanker flanked by F-111s. Was it the first appearance of America’s hypersonic spy plane? Evidence appears to contradict that theory.
The British Defense Ministry released a report in May of 2006 that stated that the US Air Force was planning on producing an aircraft flying between Mach 4 and Mach 6. That continued to fuel the rumors of the SR-91 Aurora.
The Real Spy Planes
An outstanding history of the US Air Force’s history of decades of testing and prototyping of hypersonic aircraft was done by Alex Hollings.
The SR-71 Blackbird was the US replacement for the U2. Introduced in 1964. At the time, it was the fastest and highest-flying aircraft in the world, with a ceiling of more than 80,000 feet, while setting an official record of flying at a speed of 2193 miles per hour in a straight and level flight in 1976, which was over Mach 3.
Later some of the pilots have claimed that the Blackbirds actually exceeded that number in operational flights, but those reports are classified. However, it is known that during its operational life, more than 4,000 missiles were fired at the SR-71 and none were ever shot down as the Blackbird could simply outrun the missiles fired at it.
But the Blackbird was retired because of the exorbitant costs of flying the aircraft and the improvements in spy satellite technology made the costs and threats to the pilots made the decision an easy one.
Rumors continued to swirl about the aircraft following a series of sonic booms over Los Angeles in 1991 called “sky quakes” that were heading towards Groom Lake, home to the famous “Area 51” where testing is done on secret US aircraft designs.
The SR-91 Aurora: Was It Real?
The first crack in the SR-91 Aurora theory of a hypersonic spy plane occurred shortly after that budget request.
While the Aurora was most definitely a real aircraft with the Air Force, it was the B-2 Spirit bomber.
That aircraft was tested throughout the 1980s and into the 1990s and entered active service in 1997. This was confirmed in a book titled “Skunk Works” by the former director of the facility Ben Rich, who confirmed that Aurora was the codename for the B-2 bomber.
What Gibson may have seen was an F-117 stealth fighter/bomber which was already flying at that time.
F-117 Still Looks Amazing National Security Journal Photo. All Rights Reserved.
F-117 Nighthawk in the Air Force Museum. Image Credit: National Security Journal.
F-117 Stealth Fighter National Security Journal Photo. Image taken at U.S. Air Force Museum.
While the SR-72 “Son of a Blackbird” program is a real concept and was included in an artist’s rendering of what it may look like in an Air Force video that was titled “Heritage Today, ISR and Innovation”, the Aurora was most likely a concept that never made it off the drawing board, if it ever existed at all. That plane may be an unmanned spy aircraft.
Rich says it didn’t. In his book that was published in 1994, “there is no codename for the hypersonic plane (Aurora) because it simply does not exist.”
About the Author: Steve Balestrieri
Steve Balestrieri is a National Security Columnist. He has served as a US Army Special Forces NCO and Warrant Officer before injuries forced his early separation. In addition to writing on defense, he has covered the NFL for PatsFans.com for more than 10 years and his work was regularly featured in the Millbury-Sutton Chronicle and Grafton News newspapers in Massachusetts.
