- Taylor Bailey: Before GPS or anything, how are people figuring out where they're going when they're flying these planes?

- Ami Eckard-Lee: That is a great question.

[upbeat music] [triumphant music] [cloud poofs] [Sergio coughs] - Sergio Gonzalez: Hey Taylor, what are you doing?

- Hey Sergio, I'm just writing a little story.

- Ooh, what's it about?

- It's about this airplane pilot in the 1920s.

She's flying around the country, doing all sorts of cool things during the early days of aviation history.

- Oh, cool, you should make her an airmail pilot.

Did you know there was an airmail route that went through Wisconsin in the 1920s?

- What are you doing here?

- Ah, Taylor, I'm a huge aviation nerd.

I had to come along for a ride.

Yeah, but one quick question.

How did pilots find their way in the sky in the 1920s?

- I guess we can see the ground, and we can look out for landmarks and things?

- But Taylor, what if we can't see the ground?

What if there's lots of clouds or it's nighttime?

I think that's an aviation museum.

Do you think we should stop by and ask for some help?

- We could try.

Let's go!

- All right; aye, aye, Captain!

- What are you, a pirate?

This is a plane, not a boat.

[airplane motor running] - Hey!

- Oh, hi there.

- Welcome.

This is the Kelch Aviation Museum.

Our museum here in Brodhead, Wisconsin focuses 100% on airplanes from between 1918 and 1940.

This was a time when civil aviation, so aircraft built by companies and people, was just as advanced in technology as the military.

So we call that the Golden Age of Aviation.

And the classic airplane is a biplane.

- Wisconsin has its own important connection to this period.

Wisconsin native William "Billy" Mitchell was a big supporter of a separate aviation department for the U.S. Armed Forces.

He started advocating for this as early as 1919.

Unfortunately, he faced a lot of pushback.

Most people couldn't see the potential in aviation.

But eventually, time proved Mitchell was right.

And today, Milwaukee's Mitchell Airport is named after him in honor of his contributions to the country's military aviation history.

So what is this plane that we're standing in front of here?

- This is our Butler Blackhawk from 1929.

Fun fact about this one, there were only ever 11 of this aircraft built.

Something that happened in the '20s was aviation got really popular in the United States.

So a lot of companies that were building cars or buildings and had manufacturing capabilities decided to start building airplanes because it was popular, and they thought they could make a lot of money by selling airplanes.

But then in 1929, we entered the Great Depression, and suddenly nobody could afford an enormous, expensive airplane like this.

So a lot of those companies went out of business.

And this is one of those aircraft companies that had a little peak and then went out of business.

- The years between World War I and II, about 1918 to 1939, are considered the Golden Era of Aviation.

In a relatively short span of time, planes went from wood and fabric biplanes to metal monoplanes used for a variety of purposes, including delivering the mail.

- But many of the big innovations in aviation history didn't happen in the sky.

They happened on the ground.

A huge effort was made to guarantee pilots had things like emergency landing strips and navigation aids to help them on their routes.

- All of this is even more impressive when you consider that many of these developments were taking place in the late 1920s and early 1930s, right during the major economic downturn known as the Great Depression.

- If this was built in 1929 before GPS or anything, how are people figuring out where they're going when they're flying these planes?

- That is a great question.

So in the '20s, yes, we didn't have GPS.

We just had two ways of navigating, and those are called pilotage and dead reckoning.

Pilotage, you can think of it as the skills a pilot would have, and it literally is just as you fly, visual reference to the ground.

So a river, a forest, a city.

That doesn't always work really well because the ground from above can be kind of confusing.

And back then in the '20s, there weren't as many cities, there weren't really highways the way we know them now.

So you combine that with dead reckoning, which is looking at your compass and knowing where north is, and knowing where you wanna go in relation to that, and then flying that compass heading.

By the mid '20s, about 1924, we started wanting to fly mail at night.

So somebody had the brilliant idea of making this massive dot to dot system across the country, where we wanted to fly on those routes.

And then every 10 or 20 miles, they put up a beacon tower with a light on it.

If you'd like to see that, I'd love to show you what it looks like in real life.

- Oh, yeah, yeah, let's go see it.

- Okay, that way.

- Okay.

- This is the beacon tower that would consist of the beacon tower and also a cement arrow in the ground.

And then also, this little maintenance shack.

- So you said there were lights up there.

What exactly would that look like with pilots in the air?

- Back then, there were several different kinds of beacon light signal.

So yes, they would have that rotating beacon so that you would see that flash and know, there's the beacon.

But they would also have these directional lights that were pointed more narrowly on the course.

Then you would know you were going right towards the beacon.

And then also, we used colors.

So we used red and green.

If it was a red light, that beacon tower area didn't have a landing strip.

And then if it was green, yes it did.

That didn't mean you were always gonna land there, but it was an option.

And it's good to know that ahead of time when you're flying.

- Ooh, beacon spotted, and I can even see an arrow on the ground.

- Oh, and look, it's blinking green.

That means there's an emergency strip if we need to land.

Uh, Taylor, I'm having trouble seeing the next beacon.

- How are we supposed to fly in bad weather like this?

- Yeah, I think we should go back to the Kelch Museum and ask Ami for some more help.

[television static] - Oh, you're back.

- Ami, we got a few more questions, sorry.

How would you fly if there was bad weather or you couldn't see where you were going?

- Well, that's where the next piece of technology comes in, and that is our first radio navigation system, and it's audio.

Unlike radios today in an airplane where you would actually talk to someone and say, "Here's where I am," and they'd talk back to you, this is just one-way.

You just tune your radio in your airplane into it and hear the sounds.

The sounds are coming from a transmitter station, and there are many transmitter stations on this map, and they're broadcasting just two sounds.

And those two sounds are Morse code.

- Morse code is a communication system that was developed during the mid 1800s.

It uses a system of dots and dashes, technically called dits and dahs, to represent letters and numerals.

And you can send these signals in a bunch of different ways: electronic currents, radio waves, visible light, or sound waves.

This means you can use different senses like hearing or seeing to receive messages.

Pretty cool.

- This transmitter is broadcasting two sounds in four sections.

One of those is going to be the letter N in Morse code, and one of those is the letter A.

The N is a dash and then a dot.

[boop bip] And then the A is the exact opposite.

So it's a dot and then a dash.

[bip boop] So the idea behind the transmitter and this radio navigation system is if you're flying in this area, this field where the N is being broadcast, you're gonna hear that.

You know you're in this big, wide area.

And if you're flying in one of the A sections, you're gonna hear the A.

But if you're flying where they overlap, you're gonna hear one constant sound.

[extended boop] And that area of overlap is called the beam.

And that is the track on which we would be flying to get where we want to go.

- These radio beacons had a range of 100 miles and were spaced 200 miles apart.

By mid 1933, there were 90 stations covering roughly 18,000 miles from coast to coast.

- Taylor, we've learned a whole bunch.

I think it's time for us to have some fun.

We gotta get up there.

- Let's go!

[group chatting] - Kacie Lucchini Butcher: There's no way I was going to let an episode that mentions the U.S.

Postal Service go by without making an appearance.

I'm their biggest fan.

The U.S.

Postal Service played a huge role in aviation development and technology.

In 1918, they began the first regular airmail service with a route that stretched from Washington, D.C. to New York, with a midpoint at Philadelphia.

In those early years of the late 1910s and early 1920s, flying at night or in bad weather wasn't really safe or practical.

All that changed with the introduction of things like light beacons, as well as regular routes with landing fields.

With these new developments, flying the mail became way faster than using trains.

By the mid 1920s, a pilot flying the mail could go from coast to coast in about 33 hours.

The same trip required over three days by rail.

Soon, there were additional airmail branches off the main route, including one from Chicago to St. Paul that passed through several points in Wisconsin.

- Whoa, Taylor, how was that for you?

Flying up in the air?

- It was amazing.

- So do you think you have enough now to go back and write that story?

- I'm ready.

I'm gonna go back and finish the story.

Maybe I'll write you in, maybe not.

Developments in airplanes and navigation aids helped bring about the golden era of aviation during the years between the World Wars.

Lighted airway beacons, four-course radio ranges, and radio communications revolutionized aviation by the late 1920s and early 1930s.

It's a reminder of how different technologies can work together to make big changes.

How do you find your way when you're traveling from place to place?

Try sharing directions in different ways with your friends and classmates for simple routes.

Think about drawing a map, writing a list of steps, or giving directions based on the texture of the ground or different sounds along the way.

You'll be thinking just like the pilots and engineers of the Golden Era of Aviation.

- We're doing great.

Full steam ahead.

[both laughing] On our boat.

- Producer: How was it?

- Good.

It was so much fun!

Oh my God, felt on top of the world.

[group laughing]