GUEST: It's the last remaining lithograph from the Walker Lithography Company.

My great-grandpa, Harry Walker, started the company, and I heard lots of stories growing up from my grandpa, who lived with us.

It's of immense value to us, because it is the only remaining thing...The Walker Lithography Company went bankrupt in the Great Depression.

Well, this is all we have.

The Wright brothers, they had a bike shop in Dayton, Ohio, so they really did the development of flight in this field you see here in the poster.

Uh, it's called Wright Field.

And my grandfather actually went down as a cool young man around town and made fun of him, cause every fool knew that you would die trying to fly.

So Great-Grandpa Walker actually hosted a parade when they came back from Kitty Hawk, so this lithograph was made by his company to celebrate their successful early flights at Kitty Hawk.

APPRAISER: I did a little research on the poster, and the Wright brothers' successful flight at Kitty Hawk, the first powered flight, was 1903.

And after 1903, the Wright brothers went on tour.

They took their project to Europe.

They tried to sell the idea of airplanes to European governments.

They tried to sell it to the military.

So what this poster is advertising is their great homecoming returning from Europe in 1909.

GUEST: Ah.

Okay.

APPRAISER: And the celebration in Dayton was huge.

These were hometown heroes, and it was a two-day, mammoth celebration of all things Wright.

To the best of my research, though, it's curious, I don't think there was actually a flying exhibition on that day.

So this poster is really a romantic vision, and the fact that the poster so accurately and beautifully re-creates a Wright flyer makes it of a lot of interest to people who study the history of aviation.

Now, in 1909, aviation-- no pun intended began to take off.

GUEST: Yes.

APPRAISER: And all around the world, as people were building airplanes, there began to be a lot of aviation shows.

In Europe, there were massive exhibitions of flying, as there were in America.

But this really is considered to be the first American aviation poster.

And as such, it's not just a great poster, it's also a very important historical document.

In fact, of all the images that I've seen, I consider this to be the most important poster I've ever seen come into the ROADSHOW.

GUEST: Oh, really?

APPRAISER: Now, the most important doesn't necessarily mean the most valuable.

In this case, the poster's really in bad condition.

GUEST: Yes.

APPRAISER: We have some very considerable problems.

It would be very difficult to sell it in this condition.

But the person who bought it would realize that for about $500 or $600, they could fix it up into a very presentable, saleable condition.

And once it was fixed up, I feel a safe auction estimate is $12,000 to $18,000.

GUEST: That's just lovely.

APPRAISER: In this condition, as it is, I think you could get $6,000 for it.

GUEST: Really?

Well, that's, that's more than I expected.