Delta Air Lines

Atlanta-based Delta Air Lines is one of the world's largest airlines, with a network of over 300 destinations in more than 50 countries. Delta operates a hub-and-spoke system network, where it gathers and distributes passengers across the globe through key locations in Atlanta, New York, Salt Lake City, Detroit, Seattle, and Minneapolis-St. Paul. Delta's sale of frequent flier miles, particularly to American Express, is a major driver of the firm's profits.