In 1962, the Department of Defense issued the tri-service aircraft designation system to standardize the letters and numbers that were used to identify aircraft. For 40 years, the Army and the Navy each used their own system, which can be downright confusing to modern aviation historians and casual plane spotters.

North American B-25 Mitchell. During WWII, this was known as the PBJ Mitchell in Navy and Marine Corps service. (Photo by the author)

Beginning 1924, the US Army Air Corps/Air Forces/US Air Force used a relatively simple system that was similar to what we see today. The first letter in an aircraft’s name denoted its mission, while the numbers were assigned sequentially by the Army or Air Force. P meant pursuit (Boeing P-26 Peashooter) before the P was replaced with F for fighter, B meant bomber (B-17 Flying Fortress), C meant cargo (C-46 Commando), and so on. Pretty straightforward, and there are many more types of aircraft beyond these. An additional letter at the front designated a special status. For example, X meant experimental and Y indicated an aircraft that was in testing and/or pre-production. Therefore, the Northrop YB-35 was a pre-production bomber, the 35th to be developed by the Air Force.

Northrop YB-35 (US Air Force)

But the Navy, being the Navy, had to do things their own way. In their system, which dated back to 1924, they tried to put as much information as possible into their aircraft designations. The result was an alphabet soup of seemingly arbitrary numbers and letters. But there was a method to their madness. Let’s take a look at the different parts in order. Readers are encouraged to take notes.

Grumman SBD Dauntless (San Diego Air and Space Museum)


The first letter or letters denoted the aircraft’s mission: SB for scout bomber (Douglas SBD Dauntless), F for fighter (Grumman F4F Wildcat), PB for patrol bomber (Consolidated PBY Catalina), and so on. This could be modified by the prefix X for experimental (Boeing XF8B-1).

Boeing XF8B-1 (US Navy)

The number following the mission designator was the sequential design number for a specific manufacturer. For example, the Grumman F6F Hellcat was the sixth fighter designed by Grumman. The letter that followed the number (and there wasn’t always a number) was a manufacturer’s code. For example, McDonnell was H, Boeing was B, and Vought was U, as in the Vought F4U Corsair. However, those manufacturer codes were often repeated or reused over time. B denoted Boeing, but it also meant Beechcraft or Budd, and, for a few years, all three were in use at the same time.


Vought F4U Corsair (Photo by the author)

A hyphenated number after the manufacturer code signified the design subtype (Grumman F9F-2 Panther), and a final letter denoted a modification, such as the Grumman F6F-5N, where N designated a night fighter fitted with a radar. So, like a Venn diagram, you could call any Hellcat an F6F and you would be correct, but not all F6Fs are F6F-5Ns.

Grumman F6F-5N Hellcat (US Navy)


So, putting it all together (or taking it all apart), we can decipher that XF14C-2, which looks like a wi-fi password, really means X for experimental, F for fighter, 14 for the 14th Curtiss fighter design, C for Curtiss, and -2 for the second variant of the original design, or the Curtiss XF14C-2. (Phew!) And if that weren’t confusing enough, the services used different designations when they flew the same airplane. The B-25 Mitchell bomber flew for the Army, but it was the PBJ for the Navy and Marines, while the C-47 in Army service was the R4D in Navy livery.

Douglas R4D of the US Navy (Photo by the author)

So, you can see why the DoD was keen on simplifying everything. After the adoption of most of the Air Force system in 1962, aircraft currently serving the Navy and Marine Corps had to be redesignated. For example, the McDonnell Douglas F4H Phantom II became the F-4 Phantom II in all branches, the Douglas A1D Skyraider became the A-1 Skyraider, and the Douglas A3D Skywarrior became the A-3 Skywarrior. Following the General Dynamics F-111, the numbering system started over with the F-1 Fury.


A North American AJ Savage refuels a McDonnell F3H-2 Demon. After 1962, these aircraft became the A-2 Savage and F-3 Demon respectively (US Navy).

But if the numbers stopped at 111, how did we get to the Lockheed F-117 Nighthawk? And why is it called a fighter when it’s really an attack bomber? YF numbers were often used to designate test aircraft, particularly captured Soviet aircraft. For example, a captured Sukhoi Su-17 became the YF-112, a captured MiG-23 became the YF-113, a captured MiG-17 became the YF-114, and other numbers were used unofficially by testing squadrons after that. The Nighthawk was called the YF-117 to disguise its true nature, and the number stuck. The F designation stuck too, and it may also have been a canard to mislead prying eyes, or perhaps a means to attract top pilots who didn’t want to fly an attack jet or bomber.

Lockheed F-117A Nighthawk (US Air Force)


But the confusing numbers weren’t limited to fighters. After the Convair YB-60, most of the B numbers went to guided missiles, which were effectively unmanned bombers. The last aircraft in that series was the North American XB-70, then the numbers started over again with the Rockwell B-1 Lancer. But now the Air Force has jumped from the Northrop Grumman B-2 Spirit to the Northrop Grumman B-21 Raider. How did that happen? In a word: marketing. Following an Air Warfare Symposium in 2016, the Air Force chose the number 21 for its proposed Long Range Strike Bomber (LRS-B) to symbolize the first bomber of the 21st century. So much for sequential numbering.

An artist’s rendering of the proposed Northrop Grumman B-21 Raider (US Air Force)

You can find all the information on aircraft designation and manufacturer’s codes, both before and after 1962, at Wikipedia.


Connecting Flights


If you enjoyed this post, please join in the conversation and let me know. For more stories about aviation history and aircraft oddities, head over to Wingspan.