< PrevNext > 64. Omnicom Group New York City Share 2016 U.S.-Booked Air Volume: $66 millionPrincipal Air Suppliers: Delta, AmericanPrincipal Car Rental Suppliers: Hertz, BudgetPrincipal Online Booking Tool: ConcurPrincipal Expense Supplier: ConcurPrincipal Card Supplier: Bank of AmericaBTN estimates Omnicom Group's 2016 U.S.-booked air volume decreased by more than 7 percent from the previous year. The company took a stronger stance in reducing travel costs in 2016 by restructuring class of service and implementing policy controls and new pre-trip reporting tools. It also strengthened its airline partnerships, particularly with Delta Air Lines; Delta is an Omnicom client, and they struck a reciprocal deal last year that relegated American, Omnicom's former primary U.S. air supplier, to secondary status. Hertz, Omnicom's longtime primary car rental company, also is an Omnicom client and holds a reciprocal contract. With the addition of new companies to the Omnicom Group, it has grown its travel program in EMEA and enhanced its global duty of care and travel risk management program. The company also began to share metrics by division and company network to ensure adherence to the core travel policy. Revenue increased 1.9 percent to $15.4 billion, and Omnicom's U.S. operations represented 56 percent of that revenue. The marketing, advertising and corporate communications company has more than 5,000 clients in over 100 countries. As of Dec. 31, it employed 78,500 people.