< PrevNext > 87. Aon London Share 2019 U.S.-Booked Air Volume: $48.9 million2019 Companywide Air Volume: $95.5 million2019 U.S. T&E: $138.2 million2019 Global T&E: $279.6 millionPrimary U.S. Air Suppliers: United, American, DeltaPrimary U.S. Hotel Suppliers: Marriott, Hilton, HyattPrimary U.S. Car Rental Suppliers: Avis BudgetPrimary U.S. Online Booking Tool: SAP ConcurPrimary U.S. Payment Supplier: American ExpressCard Program: Individual Bill/Individual PayPrimary U.S. Expense Supplier: WorkdayPrimary U.S. Travel Risk Management Supplier: WorldAwareConsolidated Global TMC: Amex GBTInsurance and professional services firm Aon returns to the CT100 after a one-year absence and after a year that included substantial changes to its corporate travel program. Aon in 2019 switched travel management providers and began to implement American Express Global Business Travel globally, transitioning 45 countries last year with a plan to implement 10 more through 2021.In addition, the company in 2019 changed its preferred global distribution system and further implemented the Concur Travel booking tool in more than 15 markets worldwide, allowing Aon additional options in traveler messaging to help drive supplier choices at the point of sale. The move is part of an effort to shift market share to designated Aon partner travel suppliers, which includes the continuing development of new measures designed to drive compliance.Meanwhile, Aon in 2019 reviewed and refreshed its global travel policy, revising some language regarding reimbursable expenses and evaluating permissible class-of-service rules. This year, policy language concerning booking requirements was further clarified. The company also is implementing alternative pricing strategies and tools for lodging.Aon uses HR platform Workday's expense management tool. The company had about 50,000 employees at the end of 2019 in about 120 countries, about the same as it had at the end of 2018.