Travelers who claim to be loyal customers of Southwest are sounding off after the airline announced changes Tuesday to its popular passenger perk.

The Texas-based carrier revealed several changes are being made in an effort to drive revenue growth and return to profitability shareholders expect, FOX Business reported.

These changes will include an adjustment to its checked bag policy, which allows all passengers to check two bags for free. Southwest has not yet announced how much travelers will be charged, though the fee for a third checked bag is listed at $150 on southwest.com.

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The move, announced Tuesday, is triggering strong reactions from travelers on social media, with some even threatening to stop flying with Southwest if they can no longer receive free checked bags.

“Call it what you will — boycott, mass exodus, defecting. Can we do that in a massive wave right now?” one person wrote in a Southwest Reddit thread.

“Nail in the coffin,” another person wrote.

“This was literally the last reason I still flew Southwest. Now it’s just Spirit with different colors,” another user commented in a different thread.

“I used to favor [Southwest] for the lack of baggage fees. They definitely will not be my first choice if their prices stay the same,” a Reddit user wrote.

Fox News Digital reached out to Southwest for comment.

Starting May 28, only Rapid Rewards A-List Preferred members and customers traveling on Business Select fares will get two free checked bags. Rapid Rewards credit card members will receive their first checked bag for free. Any other customers who do not fall into those two categories will be charged for both checked bags, according to Southwest’s press release.

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“It makes sense to be angry at Southwest because they have literally announced an intention to reverse their brand promise, that they have promoted as ‘transfarency’ regarding lack of fees or charges for checked baggage,” Gary Leff, a Texas-based travel industry expert and author of the blog “View From the Wing,” told Fox News Digital.

“They have dealt [with] a decades-long relationship with customers based on a simple and fair value proposition that they are changing, and loyal customers do feel betrayed.

“For five decades, Southwest has been a pioneer and a maverick, and they’ve announced that legacy has ended.”

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Other social media users said they will consider flying with other airlines, even though they were once loyal Southwest customers, but they do not think a boycott is the answer.

“I won’t boycott. I’ve flown SW a lot — but simply because I had to get from point A to point B — and SW could often provide that to me at the cheapest rate and/or the most convenient times and routes. If SW can still provide that on any particular trip, then fine. But, now other airlines will be considered more often,” another Reddit user commented.

“Sure this sucks, but like everyone has already pointed out, they’re like every other airline now, so no use in boycotting for another just like it. It’s going to come down to cheapest fair, and most convenient or direct route for me. Based on my home airport, it’s likely going to still be Southwest,” a social media user added.

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Leff said Southwest once had customer-friendly policies like flexible rebooking or its free checked bags, which helped differentiate it from the other major airlines, but these recent changes appear to have damaged the relationship between the airline and many of its customers.

“Now they’re introducing basic economy fares that will not come with seat assignments prior to check-in, even as they charge fees for such assignments to customers buying more expensive tickets. They’ve reduced points-earning on the cheapest tickets. They’re introducing checked bag fees. And they’re upending their boarding process,” Leff said.

“They will be adding extra legroom seating at the expense of legroom in standard seats,” he added.

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Leff said, compared to other airlines, Southwest lacks some amenities, like seat-back entertainment screens, fast Wi-Fi and seat options with extra legroom, all of which may discourage travelers from purchasing a ticket with the carrier.

“At the same time that Southwest minimizes the differentiation between their product and the rest of the industry, they will be behind other airlines as they chase that same model,” Leff said.

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“In other words, Southwest Airlines is giving up its competitive differentiation while positioning itself at the bottom of the industry for the model they’re chasing.”

FOX Business’ Daniella Genovese contributed to this report.