United Airlines Won't Let AI Agents Book Your Flight

If you ask an AI assistant to book your next United flight, it can find you a fare, but it won't be able to buy the ticket. United said on November 11 that it will block personal AI agents from purchasing on its systems, The Wall Street Journal reported, because they could expose customers' sensitive information or make purchases customers didn't intend.

We think United made a reasonable short-term call, but it's not a long term solution. When an agent shows up ready to pay, a seller historically had no reliable way to confirm which person sent it or what that person agreed to, and until it could, blocking was the safe default. More companies that sell online will face the same decision as agents start shopping, and verifying the person behind an agent before it acts is the job we built x401 to do.

A cautious call from a pro-AI CEO

Scott Kirby is hardly an AI skeptic. United's CEO has said AI can be a transformational tool, and he has talked about vibe-coding his own sports betting app after three hour-long sessions with a tutor. At an event in Chicago the day before the announcement, he said United would likely take a cautious approach to agentic commerce anyway. "To be honest, I don't want to create another middleman," he said.

Part of that caution is about the business, since airlines spent years fighting online travel agencies over how their tickets are displayed and sold. The rest of United's reasoning is about the people buying the tickets. An agent that books a flight is handling a traveler's personal and payment information, and when it buys the wrong thing, the traveler is the one left to sort it out. Federal rules also govern what airlines must present to travelers, and some steps can't be handed to software at all. An agent can't attest at check-in that a bag doesn't contain explosives.

Where knowing the person matters most

Other airlines have drawn the line in different places. Delta lets AI assistants complete bookings when they're authenticated, with extra safeguards for sensitive transactions like trips for unaccompanied minors. When a child is flying alone, an airline has to be sure a parent or guardian arranged the trip, and a request from software can't show that on its own.

American says some agents, including Meta's Muse, can buy its tickets through certain partners, and Southwest is testing a ChatGPT plug-in that lets customers search its flights.

Agents still book very few trips, and United said it isn't seeing many bookings from them yet. During Halloween week, Uber said, its drivers made 320 million trips across Uber and Uber Eats, and AI agents placed 500 of the Eats orders and booked four rides. Travel is where the companies building agents are heading next. OpenAI bought Odessia, a startup building AI for travel booking, this week, and Mark Zuckerberg has said travel planning is one of the top uses for Muse.

What it takes to say yes

United's systems can already tell when a booking comes from an AI agent instead of a person or a travel agency. To let that agent buy, an airline needs to know whose trip it is and what that traveler agreed to, and it needs a record it can point to if the purchase is disputed.

We built x401, an open protocol, so a site can get those answers from an agent before it acts. The traveler verifies their identity once, to NIST IAL2 with a government ID and a live biometric check, and holds the credential in a cloud wallet. They sign a mandate that names their agent and sets its limits, such as a spending cap and a time window. The airline checks every request against that mandate, turns down anything outside it, and keeps a signed record of what the traveler approved. The traveler or the airline can revoke the agent's credential at any time.

Whether to welcome agents as a sales channel remains each airline's decision, and the check-in attestation stays with the traveler. When an airline does let an agent buy, x401 tells it who the agent is acting for and what that person approved.

United also encouraged other companies to "consider measures that preserve the data and security of their customers and strengthen safety." For a company deciding whether to let agents buy, the first measure we'd put in place is a verified person behind every agent.

If you'd like to see how x401 could work in your checkout, you can book time with our team here.