American Airlines has multiple travel advisors up in arms after it announced plans to restrict AAdvantage Miles earnings for certain booking agencies.

The airline behemoth announced in February that flyers hoping to earn AAdvantage miles for their flights will have to do so directly through American, their airline partners, or preferred travel agencies recognized by the company.

The change will take effect on May 1, but American has yet to reveal which agencies will be included in its “preferred agencies.”

The change comes as part of the airline’s effort to minimize costs for agencies using older technology booking systems.

The airline has tried to convince agencies using the older booking systems to upgrade to newer platforms like the one American uses on its website.

While American announced a list would be shared in “late April,” agencies unsure if they’ll make the cut are expressing their distaste for the major change.

The American Society of Travel Agents (ASTA), Association of Canadian Travel Agencies and Advisors (ACTA), Foro Latinoamericano de Turismo (FOLATUR), and World Travel Agents Associations Alliance (WTAA) emphasized that any plans to restrict their clients’ earning miles could be detrimental to their agencies.

“It’s clear from the consensus among WTAAA, ACTA and FOLATUR, representing travel professionals around the world, the detriment that American’s decision will have on the travel industry globally,” President and CEO of ASTA, Zane Kerby, told Travel and Tour World.

Kerby called out American for “operating in bad faith” and was “looking to pad its bottom line at the expense of our valued clients and the millions of consumers who rely on their trusted travel advisor.”

Henry Harteveldt, president of the travel industry market research firm Atmosphere Research Group, told Fodor’s Travel the move is a “very inward-looking” perspective on American Airlines.

“It’s not a very consumer-friendly approach, and American is being a bit of a bully here,” Harteveldt explained — adding the move will put loyalty airline members in the crossfire of the company’s dispute with agencies.

Harteveldt believes the move is also being monitored by the company’s competitors, who may adopt the change if it’s a success or whose sales teams may swoop in to poach any American flyers unpleased with the new method.

“As risky as American’s actions are, a lot of airlines are watching to see if it works out well for them, because if it does, I would not be surprised to see United and Delta copy it in certain ways,” he told the outlet.

While the airline is deadset on the change, Brett Snyder — author of the popular travel industry blog Crankyflier and CEO of the travel assistance service Cranky Concierge — said the move could cause “confusion” for the company’s flyers who already are trying to navigate their “frequent changes.”

“The biggest impact will likely be on business travelers who may not have a choice of where to book depending upon company policy,” Snyder told the outlet.

“The fact that American still hasn’t told everyone who is or is not preferred adds more to the confusion.”

As the airline industry waits to hear who American will list as their “preferred agencies,” occasional travelers may also feel the weight of the change, Snyder explained.

He worries that some agencies may not disclose that to their customers during the booking process.

Also, the move could affect cruise lines that book airfares as part of their packages, who may opt against using certain agencies not listed as one of American’s preferred agencies.

The changes will only affect travelers who collect AAdvantage Miles for their flights on American.

Flyers using corporate accounts with American will continue to earn miles for their flights no matter which booking channel they use unless they book a Basic Economy fare.

Travelers collecting miles from other Oneworld partners—the global airline alliance American is a member of with 13 other Airlines, such as British Airways, Qatar Airways, and Malaysia Airlines—will continue to earn miles for American Airlines flights regardless of booking channel.