NEW YORK ( TheStreet) -- First of all, let us say that Chicago is among the most important U.S. cities for commercial aviation. United has its headquarters, 14,000 employees and its largest hub in Chicago. American has a hub and 8,800 employees. Chicago has two major airports including O'Hare International, the world's fifth-busiest airport. So one would expect that Chicago Mayor Rahm Emanuel would take an interest in representing the interests of the U.S.