Update 11/12/2018: I confirmed with an insider there is no doubt the SR-72 is currently in service.
In November of 1955, a C-54 US Air Force transport plane crashed in the Spring Mountains in Southern Nevada. All 14 occupants were killed. The families of the decedents knew their family members had died but they were never told what the mission was until 1998 when an FOIA provided the accident report. Flight 9068 was transporting members of the CIA and other defense contractors to Groom lake, aka Area 51 for a test flight of the U-2 Spy-plane. The U-2 was at the highest level of secrecy, probably in the the top five of secret black budget projects ever.
This was a new technology. This was the first high-altitude reconnaissance aircraft. There was no expectation of this technology. Maybe a dream of this concept, but it had to be kept under wraps so the missions could be implemented in secrecy once the U-2 passed all testing. After the public knew of the U2, there was an expectation of the next big thing in defense aviation. The public just did not know about the A-12 project designed by Lockheed for the CIA in 1960 which eventually became the SR-71 that could fly higher and faster then any aircraft on earth. This project was started as the U-2 was flying missions.
Then we had a the “Black Triangles”. The F-117 Nighthawk was the first offensive aircraft built with stealth technology. Its maiden flight was in 1981 and started overseas operations in 1983. It was flying missions from the secret Tonapah flight facility for 5 years before the general public knew of its existence. This technology, creating stealth fighters and bombers was not an expected technology by the general public. One of my business partners actually oversaw the security and secrecy at Tonapah before he retired from the military. Oh the stories I could tell.
In 2015, Coastal Californians witnessed a missile launch offshore. There were all kinds of conspiracy theories like the US Navy was conducting a mock attack on Los Angeles. What they might not have known was that in 1946, just after WW2, President Truman, created the establishment of the Naval Air Missile Test Center at Point Mugu. The Point Mugu complex works in collaboration with its sister location at China Lake NAWCWC. Most of the public did not know advanced missile technologies were being developed right under their noses.
Lets move to the present day. On January 16th, Bloomberg Technology reported the possible existence of the replacement of the SR-71 with the SR-72 called “The Son of Blackbird”. There are all kinds of theories going around about a secret aircraft called Aurora. Some people think this aircraft is just sitting in a blueprint. I however, based upon history and my poking around, feel the SR-72 has been around for 4 years to support the RQ-180 drone. The SR-72 investigates and the drone monitors the target area. We did not replace the SR-71 without a replacement and we can all conceive of an expected advance into greater defense technologies.