Heathrow Airport, the United Kingdom's busiest hub serving nearly 85 million travelers in 2025, has launched Hallie, an advanced AI customer service agent developed in partnership with Salesforce. Spearheaded by Heathrow's Director of Digital, E-commerce, and Marketing Peter Burns, the initiative aims to manage growing passenger demands through technology. Hallie, which went live on WhatsApp in March 2025, answers traveler queries regarding security wait times, amenity locations, and baggage issues without human intervention. The collaboration dates back to 2009, when Heathrow adopted Salesforce Service Cloud to unify customer data. By July 2021, this platform enabled real-time data access for airport staff. In early 2023, Heathrow began integrating Salesforce's generative AI and autonomous Agentforce tools, initially focusing on internal tasks like drafting response emails and summarizing case resolutions. This pilot phase was critical for refining the AI's accuracy before its public debut. A major challenge in deploying such systems is ensuring the AI is trained on up-to-date and accurate data. Bern Elliot, a Research Vice President at Gartner, noted that while customer contact centers are ideal environments for AI testing due to measurable outcomes, outdated data can lead to incorrect responses. To address this, Heathrow spent several months gathering and updating over 500 internal policy documents. Heathrow also expanded its data platform in July 2024 to include real-time flight tracking, which became a core feature for Hallie. The impact of Hallie has been significant. Prior to its launch, 70% of customer inquiries were handled via phone. By March 2026, the agency's autonomous capabilities reduced phone calls to just 10% of inquiries. Heathrow plans to expand Hallie to its website and mobile app later this year, with potential future deployment at terminal kiosks. To ensure reliability, the airport has implemented strict guardrails. Hallie only accesses data from Heathrow's official website and internal databases, avoiding the open web to prevent the propagation of inaccurate or outdated information. While this restriction limits the agent's ability to answer certain personalized questions, such as specific baggage claim locations, it prioritizes accuracy. Peter Burns emphasized that maintaining the integrity of information is essential, even if it curtails the scope of the agent's current capabilities. Paul O'Sullivan, Senior Vice President of Solution Engineering at Salesforce, highlighted the importance of cross-functional alignment. Successful deployment required coordination between executive leadership, engineers, and security teams to ensure internal systems were prepared. Through regular meetings and workflow analysis, the partnership identified key pain points and optimized the AI to mimic human agent workflows effectively. As the project evolves, Heathrow aims to enhance Hallie's functionality while maintaining its focus on providing trustworthy, real-time assistance to millions of passengers annually.