The Time Humans Decided to Fly Slower
and why that's weirder than you think
[Note: This is Part 1 of a 2-part series on supersonic flight. Part 2 will dive into what it means for the future of human civilization when we can suddenly have breakfast in Tokyo, lunch in London, and dinner in New York. If you're already confused about why that's important, this post is definitely for you.]
Every so often, I fall into a Wikipedia rabbit hole that makes me question everything I thought I knew about human progress. Last month, it happened when I read this mind-bending fact:
In 2024, despite having phones more powerful than the computers that sent humans to the moon, despite having cars that can (kind of) drive themselves, and despite having robots that can do backflips, we actually fly SLOWER than we did in 1973.
Let that sink in for a second.
Somewhere in an alternate universe, there's a version of us that kept pushing the boundaries of speed. In that universe, you can fly from New York to London in 2 hours, have a business meeting, and be back home in time for dinner. But in our universe, we're still crawling through the sky at the same speeds we did when people thought bell-bottoms were cool.
Why?
The answer involves a fascinating mix of physics, politics, environmental science, and human psychology. But mostly, it involves us making things go boom in ways that really annoy everyone on the ground.
Welcome to the strange world of supersonic flight.
The Problem with Going Really Fast
Before we dive in, we need to talk about what happens when things go faster than sound. And to do that, we need to understand what sound actually is.
(If you're already a physics expert, you can skip this part. But then again, if you're a physics expert, you probably enjoy reading about physics anyway, so who am I kidding?)
Sound travels through air like ripples through water. When you clap your hands, you create waves of compressed air that spread out in all directions at about 767 mph (at sea level). This is what we call the speed of sound, or Mach 1 if we're feeling fancy.
When an airplane flies at normal speeds, it pushes these sound waves out ahead of itself, like a boat pushing water. Everything's fine. The air has time to get out of the way, like a crowd slowly parting for someone walking through.
But when a plane goes faster than sound, something weird happens. The air doesn't have time to get out of the way. Instead, it gets compressed into a cone-shaped wall of pressurized air that trails behind the plane. When this wall of high-pressure air hits you, you hear a BOOM.
Actually, you hear two booms, because there's a pressure wave at both the front and back of the plane. It's like the air is getting punched twice.
This would be just a neat physics fact if it weren't for one small detail: People really, really hate being punched in the face by invisible walls of air.
The Time We Decided to Punch an Entire City in the Face (For Science!)
In 1964, someone at the U.S. government had what they thought was a brilliant idea: "Hey, let's repeatedly hit an entire city with sonic booms for six months and see how they feel about it!"
This was Operation Bongo II (yes, that was its real name), and it was conducted over Oklahoma City. For six months, the Air Force subjected the city's residents to eight sonic booms per day.
The results were... predictable:
15,000 complaints
4,901 damage claims
One very angry city
The eventual banning of supersonic flight over U.S. land
It turns out that when you repeatedly startle people, rattle their windows, and wake up their babies, they don't respond with "Wow, the march of human progress is so inspiring!" They respond with lawyers.
The Concorde
Despite this setback, in 1969, humans built something remarkable: the Concorde. It was basically a time machine.
No, really. If you left London at 10:00 AM on the Concorde, you'd arrive in New York at 9:30 AM the same day. You could literally land before you took off (local time). This is the closest humans have ever come to commercial time travel.
But the Concorde had some problems:
It was LOUD. Not just sonic-boom loud, but everything-it-did loud. Taking off? LOUD. Landing? LOUD. Just sitting there? Still pretty loud.
It was expensive. Like "sell-your-car-to-buy-a-ticket" expensive. A round-trip ticket would cost about $20,000 in today's money.
It drank fuel like a college freshman at their first party. The Concorde burned about 2 tons of fuel just taxiing to the runway.
Meanwhile, The Military Was Off Being... The Military
While commercial aviation was dealing with the sonic boom problem by essentially giving up, the military was in their secret clubhouse building something ridiculous.
The SR-71 Blackbird was what you'd get if you asked a 12-year-old to design a plane, but then actually had the technology to build it:
It flew so high (85,000+ feet) that pilots had to wear spacesuits
It went so fast (Mach 3.2+) that it had to be built out of titanium because aluminum would melt
It leaked fuel on the ground ON PURPOSE (more on this in a second)
When it got shot at by missiles, it just accelerated and outran them (this happened over 4,000 times, which is both awesome and terrifying)
Quick nerdy sidebar: About that fuel leak thing - the SR-71 was designed to expand by several inches during flight due to heat. At ground temperatures, this meant the fuel tanks had gaps. The solution? Let it leak on the ground and wait for the heat of high-speed flight to seal the tanks. This is the aerospace equivalent of saying "eh, it'll probably work out."
The SR-71 solved the sonic boom problem in the most brute-force way possible: by flying so high that the booms barely reached the ground.
But here's the thing - while this worked great for spy planes, it's not super practical for commercial travel. Airlines generally prefer their passengers to be able to breathe without spacesuits. Picky, picky.
What This Means For Humanity (The Part Where Things Get Philosophical)
So far, we've talked about the technical challenges of supersonic flight. But let's zoom out for a second and think about what it means that we, as a species, voluntarily chose to fly slower.
This is actually pretty weird when you think about it.
Throughout human history, we've consistently chosen to go faster whenever we could:
Walking → Horses
Horses → Trains
Trains → Cars
Cars → Planes
But with supersonic flight, we did something unprecedented: we developed the ability to go faster, and then collectively said, "Nah, not worth it."
This tells us something interesting about human progress. We tend to think of technological advancement as a straight line going up and to the right, but it's actually more like a negotiation between what's possible and what's desirable.
The sonic boom problem isn't really a technical problem (we solved that in 1947). It's a social problem. It's about balancing the benefits of speed against the costs to our communities.
Some numbers to think about:
A supersonic flight could save about 4-5 hours on a transatlantic journey
But it creates a sonic boom corridor about 50 miles wide
Meaning thousands of people get disturbed so a few hundred can save some time
This is basically the tragedy of the commons, but with noise pollution.
The Bigger Picture
The supersonic flight story is a perfect example of what I call a "collective action problem" (which is a fancy way of saying "thing that would be great if we could all agree on how to do it").
Other examples of collective action problems:
Climate change
Traffic in cities
That one friend who never does their dishes in the shared apartment
In each case, the technical solution exists, but the social solution is much harder.
And this brings us to where we are today. We have:
The technical ability to fly supersonic
A strong desire to fly faster
A equally strong desire not to be sonic-boomed while trying to watch Netflix
To be continued in Part 2: "How NASA and a Bunch of Startups Are Trying to Make Supersonic Flight Not Annoying"
Coming up in Part 2:
NASA's X-59: The Plane Designed to Sound Like a Gentle Whisper
Boom Supersonic: The Startup That Wants to Make the Concorde Look Slow
What Happens When We Solve the Boom Problem
Why Your Kids Might Grow Up in a World Where Distance Is Optional
As always, if you enjoyed this deep dive into the world of human progress, you might like my newsletter, where I regularly overthink things so you don't have to.