An airline is a company that provides air transport services for traveling passengers and freight. Airlines use aircraft to supply these services and may form partnerships or alliances with other airlines for codeshare agreements, in which they both offer and operate the same flight. Generally, airline companies are recognized with an air operating certificate or license issued by a governmental aviation body. Airlines may be scheduled or charter operators.
American Airlines, Inc., is a major US-based airline headquartered in Fort Worth, Texas, within the Dallas–Fort Worth metroplex. It is the world's largest airline when measured by fleet size, scheduled passengers carried, and revenue passenger mile. American, together with its regional partners and affiliates, operates an extensive international and domestic network with almost 6,800 flights per day to nearly 350 destinations in more than 50 countries. American Airlines is a founding member of the Oneworld alliance, the third-largest airline alliance in the world. Regional service is operated by independent and subsidiary carriers under the brand name American Eagle.
United Airlines, Inc. is a major U.S. airline headquartered at Willis Tower in Chicago, Illinois. United operates a large domestic and international route network spanning cities large and small across the United States and all six inhabited continents. Measured by fleet size and the number of routes, it is the third-largest airline in the world after its merger with Continental Airlines in 2010.
Southwest Airlines Co., typically referred to as Southwest, is one of the major airlines of the United States and the world's largest low-cost carrier. It is headquartered in Dallas, Texas, and has scheduled service to 121 destinations in the United States and 10 additional countries. As of 2018, Southwest carried more domestic passengers than any other United States airline.
Lists of airlines cover existing and defunct airlines. Complete lists are given in alphabetical sequence by the name of the continent from which they operate. Lists are also given by size, by business model and by other characteristics. There are over 5,000 airlines with ICAO codes. The world's largest airline by fleet size and passengers carried is American Airlines, operating from the United States.
The largest airlines in the world can be defined in several ways. As of 2019, American Airlines Group is the largest by fleet size, passengers carried and revenue passenger mile. Delta Air Lines is the largest by revenue, assets value and market capitalization. Lufthansa Group is the largest by number of employees, FedEx Express by freight tonne-kilometers, Turkish Airlines by number of countries served, Ryanair by number of routes and UPS Airlines by number of destinations served.
InterGlobe Aviation Ltd., doing business as IndiGo, is an Indian low-cost airline headquartered in Gurgaon, Haryana, India. It is the largest airline in India by passengers carried and fleet size, with a 53.5% domestic market share as of October 2021. It is also the largest individual Asian low-cost carrier in terms of jet fleet size and passengers carried, and the fourth largest carrier in Asia with over 6.4 crore passengers carried in financial year 2018–19. The airline operated 1,500 daily flights as of 2019 to 96 destinations – 71 domestic and 25 international. It has its primary hub at Indira Gandhi International Airport, Delhi.
This is a list of airline codes. The table lists IATA's two-character airline designators, ICAO's three-character airline designators and the airline call signs. Historical assignments are also included.