Delta Air Lines is the largest airline in the world, measured by total passengers and number of departures. Alongside its regional subsidiaries, which operate under the Delta Connection brand, the airline flies over 5,000 flights per day. The airline also serves a staggering 325 destinations in 52 different countries spread across six continents. Overall, Delta Air Lines is also the second-oldest commercial airline operating in the United States. It was founded nearly 100 years ago, beginning passenger operations just after United Airlines.