It's always been hard to get a job as an American Airlines flight attendant.

Now, it's getting harder to keep it.

That's the big takeaway, at least, according to a report from the union representing American Airlines flight attendants, which says American Airlines is now moving to fire flight attendants at three times the rate they were just a year or two ago.

To be clear, these alleged increases are for supposed violations of a wide variety of disciplinary transgressions, and the American Airlines flight attendants union says it's been "inundated" with calls from flight attendants who are facing possible termination.

The increase came to light during an executive committee meeting of the flight attendants union, according to the aviation news site Paddle Your Own Kanoo:

Despite well-publicized staff shortages across the aviation industry, American Airlines has made no secret of the fact that managers are looking to strictly enforce a wide range of rules and policies that may have previously been allowed to slip.

The flight attendant union, however, is concerned that some of its members are being moved to termination without meetings or "attempts to mitigate." The union is also concerned that flight attendant managers are now expected to supervise as many as 1,000 crew members each.

I asked both American Airlines and the union representing American Airlines flight attendants for comment, but haven't heard back from either.

Still, as I've reported recently, the relationship between American Airlines and its flight attendants has been fraught. Certainly, ongoing contract negotiations have something to do with that.

Recently, we've heard reports of a significant number of American Airlines flight attendants being fired for not being near their assigned bases while on reserve. 

And, reports surfaced that American Airlines was cracking down on senior flight attendants who would allegedly bid for preferred trips that they had no intention of working, and then sell the right to work those trips to more junior flight attendants.

I don't know if any flight attendants were actually fired for this, but American Airlines said at the time: "Simply put, if it's proven you're abusing our systems, the consequences would most likely be career-ending."

Now, I certainly don't like the idea of people losing their jobs -- and truly, this seems like a story in which nobody is really happy. But, nothing happens in a vacuum. And as Gary Leff of the airline site View From the Wing put it:

The American Airlines flight attendants union may not like the increased number of terminations. And the reasons in any given case may be disputable ...

But in any company with over 10,000 people serving in a role, there are going to be some people who aren't good fits and should be asked to leave.

I think that's the big takeaway here. I've written a lot about the importance of developing and maintaining culture in big organizations. 

It's a business truism that we hear over and over, to the point of cliché -- but like a lot of clichés, it's also true: If you want to be a great leader, building a great culture matters most.

Sometimes, we do that in positive ways: Setting standards, creating incentives, leading by example.

But sometimes, we're also forced to do that in more negative ways -- for example, by finding the small percentage of team members whose actions suggest they aren't really buying into the culture, and looking for ways to remove them.

Or, as a former boss of mine used to put it euphemistically when we discussed firing poor performers: Give them the opportunity to find a better fit at another company.

The process can be difficult, and messy, and unpleasant. But it's important: You're not only removing people who aren't fitting in, you're also making clear to everyone else what's acceptable and what isn't.

I want to be clear: I don't know any of the specific cases of flight attendants losing their jobs at American Airlines. They may all have legitimate grievances. 

But, the specifics don't really matter for our purposes. Frankly, when I write about airlines, I'm mostly looking for the lessons business leaders can take to other industries.

As I write in my free ebook, Flying Business Class: 12 Rules for Leaders From the U.S. Airlines, this is one of the few publicly traded commodity industries in which every single development is dissected by a legion of analysts, investors, and journalists.

It's like a nonstop parade of business school case studies, each teaching another valuable lesson.

Today's lessons? Culture matters most. And sometimes, bad news sends a much-needed message.