The US Air Force was a thing long before we knew it by that name.

For 40 years, from the DIY days of the Wright Brothers to the hellish dogfights of World War II, the US military has flown dozens of different aircraft and thousands upon thousands of missions. But for the most part, these flyers served as members of the US military. (With no disrespect, of course, to the many US Navy pilots. Here, however, we focus on the branch dedicated to air superiority.)

Then, two years after the end of World War II, came the National Security Act of 1947. The act, which President Harry Truman signed on July 25 of that year, decreed that the army of l air should be its own separate branch of the US military. , effective two months later, on September 18.

Thus the US Air Force was born at the dawn of the age of jet aircraft, nuclear weapons and supersonic flight. This year marks the 75th anniversary.

He had barely begun his new bureaucratic existence when he recorded a remarkable aerial achievement: Captain Chuck Yeager breaking the sound barrier in the X-1 aircraft, October 1947. But more everyday designs were the norm, such as the former C-47 Skytrain. , an emissary of hope and rations for those bottled up in a divided city during the Berlin Airlift, and soon the B-36 and B-52 bombersavatars of Cold War doctrines of mass retaliation and mutual assured destruction.

Over the past few decades, the Air Force has been at the forefront of aviation with stealth aircraft, including the F-117 Nighthawk and B-2 Spirit, with Predator and Reaper drones, and with the X-37B secret space plane.

The first slideshow looks back over 75 years of US Air Force aircraft. The second, below, features the 40 years of aircraft that arrived first.

Before 1947, the precursors of the US Air Force went by many names. It all started with, among other things, the Army Signal Corps. In the early years of powered heavier-than-air aircraft after the Wrights flew at Kitty Hawk, people viewed flying machines—balloons and airships included—as observation platforms more than weapons.

Here’s how the naming of the organization went over the years before Washington created the US Air Force: the Aeronautical Division (1907-14) and Aviation Section (1914-18) of the Signal Corps, the Army Air Service (1918-26), the Army Air Corps (1926-41) and Army Air Forces (1941-47).

The Aircraft Division began operations on August 1, 1907. Two years later, the U.S. government officially accepted a Wright Flyer at a cost of $30,000 and designated it Signal Corps Airplane No. 1.

And new planes keep coming. The Air Force is now considering the B-21 Raider, a next-generation bomber that, on paper, bears a strong resemblance to the existing B-2 Spirit bomber. The service is trying to think carefully about the future, saying the B-21 will be “the backbone of the Air Force’s future bomber force.” It will serve with the latest versions of the long-serving B-52, while the B-1B is being phased out.

The B-21 is currently in development at Northrop Grumman. In May, the defense contractor completed an initial series of tests, calibrating instruments and verifying the structural integrity of the first B-21, part of ground testing before the eventual first flight. The company said it has six planes in various stages of production and testing.

The Air Force projects the first flight of the B-21 Raider to be in 2023 and expects the first wave of aircraft to be operational in the mid-2020s. It plans to spend about $20 billion over the course of five years for B-21 production, plus $12 billion for R&D, but he didn’t say how many planes that would be.

As of 2016, the Air Force was eyeing at least 100 of the B-21 aircraft once production reached full speed.

While the generals, bureaucrats and politicians sort things out, the pilots will be out there doing their thing: flying.

Here’s Yeager on the nature of the hot-shot pilot. It was 1954, and he had just tested a high-performance Soviet MiG-15 delivered by a defector, which he compared to the Air Force’s F-86 Saber.

“Yeager must have laughed. Some things never changed,” wrote Tom Wolfe in The Right Stuff. “You let any fighter jock talk about the enemy plane and he’ll tell you it’s the hottest thing that ever left the ground. After all, it made him look even better when he got waxed the bandit’s tail.”