United Airlines wants to outsource up to 2,000 jobs at 28 U.S. airports to outside vendors, it announced Monday. America's No. 2 carrier by traffic would fire workers in areas like check-in, baggage-handling, and customer service at its smaller hubs. The International Association of Machinists' contract with United protects jobs at big hubs like Newark and O'Hare, but not jobs at smaller hubs. United has been trying to cut $2 billion from its annual costs since 2013 and reported $37 billion in operating expenses that year, giving it one of the lowest profit margins among its peers.