As of 2015, some of the larger American-flagged airlines operating in the United States include Delta, American, Southwest and United. Regional carriers include Hawaiian Air and Alaska Airlines. Foreign-flagged carriers include Air Canada, Qantas, Air France, British Air and Japan Airlines.
The first four carriers are the major players. Delta began as a crop-dusting service, evolving into a passenger service during the 1940s. Their Atlanta headquarters, still in use today, officially received the Historic Aerospace Site designation from the American Institute of Aeronautics and Astronautics in 2011. Delta is now a worldwide carrier.
American Airlines began as American Airways, a company that consolidated several small airlines to create a single large company. One of the original airlines included was Robertson Aircraft Company, co-owned by famous aviator Charles A. Lindbergh. It became American Airlines in 1934 and is now a major worldwide carrier.
Southwest Airlines started in 1967, but due to a number of legal challenges by existing airlines, didn't start flying until 1971. It started as a regional carrier in the Texas area but now flies throughout the United States and into Mexico and the Caribbean.
United Airlines started out as a cargo and mail carrier based in Boise, Idaho. Known as Varney Airlines, it flew its first mail flight in 1926. Passenger service started in the 1930s, with United entering the overseas market in 1983 with flights to Tokyo, Japan.