Delta Air Lines Delta Air Lines, based in Atlanta, Georgia, is one of the largest and oldest airlines in the world. Delta operates a vast domestic and international network, serving over 300 destinations in more than 50 countries. Known for its reliability and extensive SkyMiles loyalty program, Delta offers multiple cabin classes including Delta One (business/first class on international and transcontinental flights), Delta Premium Select (premium economy), Delta Comfort+ (extra legroom economy), and Main Cabin (economy).

American Airlines American Airlines, headquartered in Fort Worth, Texas, is another major airline with a comprehensive route network. It serves nearly 350 destinations in more than 50 countries. The airline's frequent flyer program is AAdvantage. American Airlines offers a range of classes such as Flagship First and Flagship Business on long-haul international flights, Domestic First Class, Premium Economy, Main Cabin Extra (extra legroom economy), and Main Cabin.

United Airlines Based in Chicago, Illinois, United Airlines is one of the largest carriers in the world by number of destinations served. United is a founding member of the Star Alliance and operates hubs in several major U.S. cities. Its MileagePlus program is popular among frequent flyers. United offers Polaris (international business class), United First (domestic first class), Premium Plus (premium economy), Economy Plus (extra legroom economy), and Economy.

Southwest Airlines Southwest Airlines, headquartered in Dallas, Texas, is known for its low-cost business model and point-to-point routing. It primarily operates within the United States and to some international destinations in Mexico, Central America, and the Caribbean. Southwest does not offer traditional seat classes but provides an all-economy service with benefits such as no change fees and two free checked bags. Its Rapid Rewards program is highly regarded among budget travelers.

JetBlue Airways JetBlue Airways, based in New York City, is a low-cost carrier known for its high-quality service and in-flight entertainment. It serves destinations in the United States, Caribbean, and Latin America. JetBlue offers classes such as Mint (premium class on select routes), Even More Space (extra legroom economy), and Core (standard economy). Its TrueBlue loyalty program is popular among passengers seeking flexible rewards.