It’s one of the best visual gags in a movie filled with them.

In the classic 1980 comedy Airplane!, two passengers are seen reading magazines. First, we see a nun reading Boys’ Life. Moments later, there’s a boy reading Nuns’ Life.

The scene is over in seconds, but the memory of this joke lives on. That’s especially true for those of us who have been reading Boys’ Life since we were kids.

Here are seven things you might not know about this bit of visual humor.

1. That’s a real copy of Boys’ Life.

Airplane! was filmed in 1979 and released in 1980. But the filmmakers chose a copy of Boys’ Life from more than a decade earlier.

In a search through the Boys’ Life archives, I found a match: the April 1968 issue. The cover photo, taken by Tom Burnside, previews a feature about fly-fishing.

Why pick that issue? It’s only speculation, but I bet the props team wanted an issue with a simple cover that had little to no text. They likely wanted a viewer’s eye to go right to the magazine title.

Alternate theory: Someone brought in a bunch of copies of BL from their private archives, and this was the favorite.

(P.S.: This and every issue of Boys’ Life is available in our app. Just search Boys’ Life in your device’s app store.)

2. That’s not a real copy of Nuns’ Life …

… Because there’s no such thing as Nuns’ Life magazine. The one depicted above might be the only copy ever made.

Photoshop hadn’t been invented when Airplane! was released, so the film’s creators had to get creative. One oft-shared (but unconfirmed) rumor says that a male production assistant dressed up in a nun’s habit and got on a surfboard to shoot that cover photo.

The face was darkened and obscured so viewers would assume the surfer is a woman.

If that story is true, it shows you how far filmmakers will go for a three-second joke.

3. The Nuns’ Life cover was placed on an old Boys’ Life.

Busted! Joey wasn’t even reading Nuns’ Life. He was reading a copy of Boys’ Life behind that Nuns’ Life cover.

How do we know? Look at the Schwinn ad on the back. I found it in the BL archives — on the back of the May 1968 issue.

That’s the issue one month after the April 1968 Boys’ Life held by the nun.

4. Nuns’ Life costs more than Boys’ Life.

The copy of Nuns’ Life depicted in Airplane! is the June 1979 issue. It sold on fictional newsstands for $1.

For comparison, the June 1979 issue of Boys’ Life cost just 70 cents.

The nun’s April 1968 BL had an even lower newsstand price: 40 cents.

5. The actress who played the nun still has this photo in her office.

Maureen McGovern played Sister Angelina, the singing, guitar-wielding nun who is spotted reading Boys’ Life.

McGovern wasn’t a film actress for long. She took her talents to Broadway and to the music industry to start successful careers in both.

But she never forgot about Airplane! Here’s what McGovern told A.V. Club in 2015:

“I know that I have, framed in my office, a press pic of my Sister Angelina looking puzzled at Boys’ Life partnered with Joey savoring Nuns’ Life.”

6. We know what page of Boys’ Life the nun was reading.

We know the nun was reading the April 1968 issue, but which article caught her fancy?

We can see a little corner of text — the word “week” — in an advertisement on the top right of the right-hand page.

Through the magic of just looking through every page to find a match, we know she was reading pages 34 and 35. The article was a piece of fiction by William Fitzgerald about a baseball player.

The ad on the right side was for a contest being run by Healthdisc, a barbell maker.

7. They even got the apostrophe right.

Props to the props team for getting one essential detail right: the name of the magazine.

Ever since it debuted in 1911, the magazine for all boys has been called Boys’ Life — not Boy’s Life.

And so, fittingly, the magazine for all nuns is called Nuns’ Life — not Nun’s Life.

Airplane! is rated PG, but it was released before the PG-13 rating was a thing. Today, it would be rated PG-13 or R. Common Sense Media, my go-to source for determining a movie’s appropriateness, recommends the movie for audiences 14 and up.