Delta Air Lines, Inc. · Atlanta, GA United States ·(NYSE: DAL)

Just as a delta is a symbol for change in math, Delta Air Lines symbolizes the changing mathematics of the airline industry. Delta became the world's largest airline by traffic after its $2.8 billion October 2008 acquisition of Northwest Airlines. Through its regional carriers (including subsidiary Comair), the combined company serves more than 375 destinations in more than 65 countries, and it operates a mainline fleet of about 775 aircraft. Delta is also part of the SkyTeam marketing and code-sharing alliance (allows airlines to sell tickets on one another's flights and thus extend their networks), which includes carriers such as Air France and KLM. To read the full description, subscribe now.