To understand why this is such a big deal, you have to know first that Southwest is by far the biggest 737 Max customer in the United States, with 34 of the planes among its fleet, and plans for many more.
Currently, those planes are mostly parked in a "boneyard" in the California desert, waiting for Boeing and the federal government to clear them for safe flight.
So, it makes sense that all eyes are on Southwest as Boeing weathers this storm, tries to fix the 737 Max after two fatal crashes, and hopes to restore faith in the plane.
Now, Southwest chairman and CEO Gary Kelly has spoken out boldly about the situation--and the 737 Max's future with Southwest.
Speaking at a chamber of commerce event in Dallas, Kelly said Southwest has no plans to abandon the 737 Max. In fact, he said it will purchase "hundreds" more 737 Max aircraft.
"It's a very good airplane, but Boeing has acknowledged that they've got some things they need to address with the software in that airplane," Kelly said, according to the Dallas Business Journal. "It seems like it's a relatively straightforward modification. We're obviously anxious to get the airplane back in service."
That's it: all-in on the 737 Max. Or at least close to it. This despite the fact that some Southwest passengers are taking to social media to decry flight cancelations, and out of fear that they were flying on a Southwest 737 Max.
(They weren't; it was just a misunderstanding. Southwest just used the same safety briefing card on several 737 variations.)
Granted American Airlines has said it's not bailing on the 737 Max, and United Airlines executives speaking on an earnings call this week seemed confident the 737 Max will return to service later this year.
But buying hundreds of the aircraft? Southwest is in a class by itself in the United States on that count. And the explanation behind that opens the door to a lot of other things as well.
The airline that only flies 737s
There are a lot of differences between Southwest Airlines and the other three of the "Big 4" U.S. airlines: a focus on domestic U.S. travel, a single fare class, and the fact that Southwest bundles the price of flight changes and checked bags into the price of a ticket, to name a few.
But there's also the fact that unlike American, Delta, and United, Southwest Airlines flies only one type of plane: variations of the Boeing 737.
In fact, there's been a lot of speculation that the 737 Max was susceptible to the flaw that may have caused the crashes in Indonesia and Ethiopia precisely because Boeing was so eager to ensure its new plane could be called a newer version of the 737, as opposed to another plane entirely--for both marketing and pilot training purposes.
But that puts an airline like Southwest, which relies 100 percent the Boeing 737 for its entire fleet, in a really tricky position.
Do one thing, over and over
There's a real debate going on this issue--and I guess it has parallels in almost every other industry.
You can choose one thing, do it over and over, and probably become pretty good at it. Or else you can diversify.
By flying just one aircraft, Southwest knows that almost any of its pilots can fly any of its planes. Its scheduling and maintenance tasks become a lot easier than for airlines with multiple types of aircraft.
But it also means that, ultimately, Southwest's brand and its overall success are tied up with Boeing and the 737 in a way that few other airlines are. Certainly none in the United States.
So, if passengers grow to distrust the 737--or even just the 737 Max variation--it's very bad news indeed for Southwest.
All in, all in
I sincerely hope that Boeing's fix will make the 737 Max as safe as any other airplane. I suspect they'll succeed at that.
But will customer faith follow? I'm skeptical--as is President Trump, who tweeted last week that no matter what else happens, Boeing needs to re-brand the aircraft.
So, I think the solution will have to be something radical.
I suggested recently having Boeing invite its rival Airbus to assess the safety of the 737 Max once it's fixed. I know that's going to be a tough sell within Boeing.
So barring that, maybe the top Boeing executives could volunteer to go on a round-the-world trip aboard a randomly selected 737 Max--bringing their families along for good measure. And I hate to say this--but top airline execs would have to go, too.
Because I don't think people care how many planes you order, or how many times you assure them that the plane is safe.
They have to see with their own eyes, hear with their own ears, and feel it deeply within their hearts. Otherwise, they'll always associate the 737 Max with something else.
And it will be hard to find the upside to buying so many of them.