American Airlines, Inc., commonly referred to as American, is a major American airline headquartered in Fort Worth, Texas. It is the world's largest airline when measured by fleet size, revenue, and scheduled passenger-kilometres flown, and the second largest by number of destinations served. American together with its regional partners operates an extensive international and domestic network with an average of nearly 6,700 flights per day to nearly 350 destinations in more than 50 countries.
Delta Air Lines, Inc. is a major American airline, with its headquarters and largest hub at Hartsfield–Jackson Atlanta International Airport in Atlanta, Georgia. The airline along with its subsidiaries and regional affiliates operate over 5,400 flights daily and serve an extensive domestic and international network that includes 319 destinations in 54 countries on six continents, as of October 2016. Delta is one of the four founding members of the SkyTeam airline alliance, and operates joint ventures with Air France-KLM, Alitalia, Virgin Atlantic, and Virgin Australia. Regional service is operated under the brand name Delta Connection.
The airline was established in 1967 by Herb Kelleher and adopted its current name in 1971. The airline has more than 52,000 employees as of July 2016 and operates more than 3,900 departures a day during peak travel season. As of 2014, it carried the most domestic passengers of any U.S. airline. As of July 2016, Southwest Airlines has scheduled services to 98 destinations in the United States and seven additional countries with service to three airports in Cuba expected to begin later this year, subject to governmental approvals.
United Continental Holdings, Inc., commonly referred to as United, is a major American airline headquartered in Chicago, Illinois. It is the world's largest airline when measured by number of destinations served, operates a comprehensive domestic and international route network, and has significant presence in the Asia-Pacific region. In the late 1920s, just prior to the use of the United Airlines name, The Boeing Company, currently one of the world's largest aircraft manufacturers, operated a predecessor airline. United was previously known as United Air Lines.