There was once an unwritten rule in the airline industry that made mentions of disaster during a plane trip a clear taboo.

After the mandatory lecture from flight attendants about emergency procedures, the crew quickly encouraged passengers to think more pleasant thoughts.

Photos and updates from 9/11 anniversary observances around the U.S. and world _lowres

A U.S. flag is draped on the side of the Pentagon, Friday, Sept. 11, 2015, where the building was attacked on September 11th in 2001, on the 14th anniversary of the attack. (AP Photo/Jacquelyn Martin)

The in-flight movie would not, it was safe to assume, be a blockbuster about terror at 30,000 feet. And those airline magazines in your seat pocket would include colorful features about the joy of travel, not the threat of terrorism.

So I was surprised, given the enforced good cheer of plane journeys, to open an issue of the onboard periodical recently and find a story about 9/11 waiting inside.

I was flying to Canada and, by coincidence, the article was about the goodness of a small Canadian town in helping Americans after the Sept. 11, 2001, terrorist attacks.

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Canada has a special place in Louisiana history as the home of Acadians expelled from the present-day provinces of Nova Scotia, New Brunswick and Prince Edward Island during the 18th century. Some of those who were displaced ended up in Louisiana, establishing the Cajun culture that’s so vividly shaped the state’s identity. The tragedy of the Great Expulsion notwithstanding, Canada’s broader cultural tradition is one of openness — which is why, or so I’ve always thought, the Cajun gift for hospitality makes perfect sense. It seems to reflect the Cajuns’ long-ago origins in a country where the welcome mat, not the wearying bigotry of the Expulsion, was the defining national trait.

All of this came to mind as I sat near the plane window and read the story of Beverly Bass, an American Airlines pilot who was captaining a nonstop flight from Paris to Dallas the day the World Trade Center towers fell. “When U.S. airspace closed, we received orders to land in tiny Gander, Newfoundland, where we would join 37 other diverted commercial aircraft,” Bass recalled. “All told, about 7,000 passengers descended on the small Canadian town, nearly doubling its population.”

For the next 21 hours, passengers and crew had to remain in the grounded planes.

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“But the people of Gander were phenomenal,” Bass added. “They delivered everything you could imagine throughout the night to the planes — diapers, formula, nicotine patches. They even filled 2,000 prescriptions for people who had packed their medicine in their checked bags.”

The miracles didn’t stop there. “When we got off the planes the next morning,” Bass recalled, “tables of food lined the airport. The residents stayed up all night cooking for us. Over the next few days, as we waited for U.S. airspace to reopen, Gander treated us like family, opening their homes and hearts.”

The story of what Gander did has since been made into a musical that debuted on Broadway this year. That’s what I learned by reading about 9/11 on a plane flight, something I didn’t at first want to do. But I’m glad I did.

Follow Danny Heitman on Twitter @Danny_Heitman.