United Airlines is the top provider in terms of expense account spend, according to AppZen, an AI-based expense report provider. In a report based on its aggregated data, AppZen said Delta Airlines was second in spend while Marriott was third, American Airlines fourth and Hilton fifth. The company also found that Uber now accounts for 57.7 percent of expensed rides but only 41 percent of expensed dollars in the category, while Lyft accounts for 13.1 percent and 10.6 percent, respectively; traditional taxis account for 29.2 percent and 48.3 percent, respectively. In fact, Uber is the most expensed vendor across all categories. Other findings: “adult entertainment” (including strip clubs, etc.) represents 16.2 percent of all rejected spend in the “unauthorized merchant” category, second to spas; Starbucks is the most expensed restaurant, while the most expensive meals are in hotels; and business travelers in the technology and management consulting industries have a lot of leeway, with 94 percent of unauthorized expenses approved in those segments, 12.1 percent more than the industry average.