If you were presented with a photo of the Lockheed A-12, chances are you probably answered that it was an SR-71 Blackbird. Don’t feel bad about it. We don’t blame you. Honestly, it’s a mistake anybody could make, especially because of their physical similarities. Anybody without intimate knowledge about these two very special aircraft could mistake an A-12 for an SR-71 and vice-versa.

Chances are that military buffs would answer the world-famous SR-71 Blackbird as it was the more known aircraft of the two. Many would even say they’re basically the same aircraft, but they couldn’t be more different!

Let’s delve into the history of these military planes to get a better grasp of both.

The CIA Top Secret A-12 Oxcart

Ah yes, the legendary SR-71 Blackbird that everybody knows because of its speed and its science-fiction-like design which had never really fallen out of style. Many would say it looks like a plane that came straight out of a Star Wars movie!

Many wouldn’t know that the SR-71’s design actually came from the top-secret A-12 Oxcart! So, where did this futuristic aircraft come from anyway? The Lockheed A-12 was designed for the Central Intelligence Agency (CIA) in 1959 for top-secret reconnaissance work as a replacement for the Lockheed U-2 spy plane, another equally famous aircraft.

The story started when a U-2 spy plane was detected by the Soviet Union in 1960 while taking photographs in Soviet airspace, consequently getting shot down in the process. It was the height of the Cold War, so of course, the two countries were spying on each other. That wasn’t really much of a secret today. What was a secret was the U-2 spy plane, which the Soviets now discovered despite the US government claiming it was a weather research aircraft. With a shape designed to reduce radar cross-section and reconnaissance equipment abroad, the shot down U-2, the Soviets knew it wasn’t a weather research aircraft.

With their cover blown, the US government needed a new reconnaissance spy plane that was faster and could fly higher to avoid detection and evade anti-aircraft attacks. So they enlisted the help of Clarence “Kelly” Johnson along with Lockheed’s Skunk Works to design the new spy plane. It had some competition. However, Johnson would be competing with Convair’s FISH and Kingfish designs due to their smaller radar-cross sections.

So in 1957, they got to work and called the initial designs “Archangel” as the U-2 program had been known as “Angel.” Designs would then on be called Archangel-1 through eventually, Archangel-12 or A-12.

The design was said to be flawless and superior compared to other aircraft of its time. It had to be considering the CIA wanted the plane to be undetectable, fly higher than 90,000 feet (or higher), and fly faster than 2,000 mph (or faster). This is where designers and their manufacturers had problems. Higher speeds meant that it needed to be heat resistant, more so it needed to be lighter to save up on fuel and climb higher. The mere friction with the atmosphere flying at 2,000 mph would melt the aircraft’s frame and possibly heat up its fuel.

So what was a good metal that could withstand hot temperatures and be lighter than your traditional steel? Titanium. But another problem arose, where would the US get enough titanium to test and build multiple aircraft?

The US, of course, had their suppliers, but these supplies simply were not enough. So they did what any clever person would do. The CIA set up dummy companies to purchase and source the metals from the country that was the largest titanium producer in the world, the Soviet Union,. So in a way, the Soviet Union would have a big impact on the development and creation of the A-12 and, later, the SR-71, which was also made of Titanium.

The project had its first unofficial maiden flight on April 25, 1962. Subsequent trials would take place at the Groom Lake Test Facility, otherwise known as Area 51, the highly classified United States Air Force (USAF) facility. A total of 13 A-12 would be built and used from 1967 to 1968, specifically on Operation Black Shield over North Vietnam and North Korea flying from Kadena Air Base on Okinawa. It was initially not tracked and detected over Chinese and North Vietnamese airspace. However, it was eventually detected in 1967 when Soviet surface-to-air missile sites tracked the A-12 and proceeded to fire at it with the Fan Song guidance radar. While they didn’t hit the aircraft, they were extremely close to the A-12 at 300 feet away.

Due to budget constraints with the SR-71 deployment in 1967 underway, the A-12 was deemed too costly to continue as the SR-71 was cheaper to fly and had a major advantage over the A-12. The SR-71 had side-looking radar and cameras, which meant it could gather information and reconnaissance data without flying overhead into enemy airspace. This would be vital since the US could no longer do reconnaissance flights over the Soviet Union, making the aircraft obsolete.

The Replacement: The SR-71 Blackbird

Despite A-12 being faster and could fly higher at Mach 3.5 and 95,000 feet, respectively, compared to the SR-71, which flew at Mach 3.3 with a maximum altitude of 85,000 feet, the SR-71 had a higher maximum unrefueled range of 3,250 miles when compared to the A-12’s 2,500 miles. More so, the SR-71’s sensor payload was higher than the A-12 at 2,500 lbs.

The SR-71, as you all know, is no joke despite its side-by-side comparison with the A-12. Also designed by Lockheed Martin’s Clarence “Kelly” Johnson, the Blackbird is the stuff of science-fiction with its titanium body and radar countermeasures. It could quickly outrun fired SAMs if it were being chased. It could simply just accelerate away and climb up to avoid these missiles. Target locking for SAMs also was deemed challenging as it was too fast for the system. More so, special radar-absorbing materials were also added to the aircraft to make its radar signature reduced. In a way, the SR-71 is a refined version of the A-12.

Read Next: Pic of the Day: SR-71 Blackbird, A Profile in Speed

After the A-12 was retired, the Blackbird took over its reconnaissance work over North Vietnam, Laos, the Middle East and was once used by the Royal Air Force in the United Kingdom. During its 30 year span of service, it was never shot down and set world records that the A-12 had never reached despite it being capable (although there are anecdotal accounts that it surpassed SR-71’s records). The SR-71 Blackbird set the world record for highest altitude flown at 85,069 feet, with a top speed of 2,193.2 miles per hour or Mach 3.3. After the Blackbird’s operation was halted in 1990, NASA would use it in 1999 for aeronautical research. Ultimately, these planes would become obsolete as reconnaissance satellites and drones would be developed.

Yup, the SR-71 was heavier and could fly at a slightly lesser speed and a lesser altitude, but it was the one to serve longer and set records. It required a two-man crew to fly compared to just a pilot with the A-12, but ultimately, it would be more beneficial to have the SR-71 do the reconnaissance work as it wouldn’t be in constant peril of Soviet SAMs. Plus, the US Air Force could actually use it, unlike the A-12, which was solely built for the CIA. Both are equally impressive aeronautical engineering marvels as they are technically part of the same Blackbird family. Still, ultimately one was more advantageous to the US, and the other, while short-lived, had done its job for the States as well.

But hey, the SR-71 vs. A-12 debate is very much still alive, so feel free to share your thoughts with us through the comments section.