United Bans AI Agents From Booking Tickets; Delta and American Hold Back

United Airlines rewrote its contract of carriage on Wednesday to prohibit AI agents from making, modifying or servicing tickets, or purchasing any service or product on its system — the first outright AI-agent ban among the three largest U.S. carriers.

The Chicago-based airline spelled out its reasoning in a statement. Third-party AI assistants can expose passengers' sensitive information, it said, and their actions can trigger unintended purchases or account changes. There's a regulatory angle too. United noted that automated AI actions could violate Federal Aviation Administration or Department of Transportation rules. Check-in is the clearest example: passengers must personally acknowledge that their bags contain no banned items, and an agent acting on their behalf can't honestly do that for them.

That's the strongest argument in the policy. The data-privacy one is fuzzier, since United didn't name a specific incident, a breach, or a single AI tool it caught misbehaving. The statement gestures at precedent instead. United cited banks and retail companies that have restricted AI agents, adding: "We encourage others to consider measures that preserve the data and security of their customers and strengthen safety."

What changes for passengers?

The mechanics are blunt. A passenger who delegates booking or ticket changes to an AI assistant now violates United's contract of carriage — the legal agreement every traveler accepts at purchase. Servicing counts too, so ancillary purchases, seat changes and similar transactions fall under the ban when an agent executes them.

Enforcement details went unmentioned. United's statement doesn't say whether it will detect automated traffic, block it at login, or act only after something goes wrong. Without detection specifics, the policy reads more as legal cover than a technical wall.

How are Delta and American responding?

Not following — yet. Both carriers told Fast Company that AI tools still hold booking privileges on their systems, though both are watching closely.

Fort Worth, Texas-based American Airlines said AI-assisted travel shopping and booking are evolving quickly, and that it will keep evaluating how best to serve customers. "Some AI tools are able to facilitate the purchase of American Airlines tickets," the company said in a statement. "At the same time, protecting our customers and their experience remains our priority. We actively monitor traffic across our website and app and can investigate, manage or block automated traffic when necessary."

That monitoring language matters. American is claiming the technical capability United's announcement left unspecified: detect, investigate, block.

Delta drew a sharper line. A spokesperson said an AI tool can complete a booking if it authenticates the passenger's credentials — but passengers remain responsible for overseeing and authorizing everything an assistant does on their behalf. "We currently support certain interactions with AI assistants when they can be appropriately authenticated, while maintaining additional safeguards for sensitive transactions," Delta said in a statement. "We're continuing to evaluate how new technology, including external AI agents, could enhance the way customers engage with Delta, always with security and the customer experience in mind."

So the industry's largest three carriers now hold three distinct positions: banned, monitored, authenticated.

What about Southwest, JetBlue, Alaska and Frontier?

They stayed quiet. Representatives for Southwest Airlines, JetBlue Airways, Alaska Airlines and Frontier Airlines didn't immediately respond to Fast Company's requests for comment.

Southwest's silence is notable because the airline moved the opposite direction just last month. It launched a plugin partnership with ChatGPT to "offer a simpler, more direct path from inspiration and discovery to booking options" — a first-of-its-kind U.S. airline plugin, per the announcement. If Southwest clarifies whether the plugin coexists with United-style restrictions, the industry's direction will get clearer.

Did markets react?

Barely, and ambiguously. United shares fell 1.8% on Wednesday while the broader S&P 500 Index rose 1.3%, a gap too small to attribute to a booking-policy change alone.

Airlines copy each other habitually — bag fees, basic economy, the whole playbook. United has now set the template for restricting AI agents, and its statement openly invites rivals to adopt it. Whether Delta's authentication model or United's prohibition becomes the industry default depends on how the first high-profile incident involving an AI-booked ticket plays out.