Delta Air Lines, Inc. (NYSE: DAL), typically referred as Delta, is a major American airline, with its headquarters in Atlanta, Georgia. The airline, along with its subsidiaries and regional affiliates, operates over 5,400 flights daily and serves an extensive domestic and international network that includes 325 destinations in 52 countries on six continents, as of 31 March 2019. Delta is a founding member of the SkyTeam airline alliance. Regional service is operated under the brand name Delta Connection. One of the four remaining legacy carriers, Delta is the sixth-oldest operating airline by foundation date, and the oldest airline still operating in the United States. Among predecessors of today's Delta Air Lines, Western Airlines and Northwest Airlines began flying passengers in 1926 and 1927, respectively.