On March 12, 1979, the company was incorporated as Atlantic Southeast Airlines, Inc. with headquarters established in the Atlanta area. June 27 saw the start of operations with one 19-passenger Twin Otter aircraft between Atlanta and Columbus, Georgia. From 1979 to 1999 the call sign for ASA was "ACEY". In 1999 there was confusion with call sign for the Federal Aviation Administration (FAA)- New Mexico based fighter unit w/ call sign "ACER". The FAA insisted one change call its sign and ASA was the one to change since they had used the call sign for the least amount of time. June 27, 1999 ASA changed to call sign CAA "Candler" after the founder of Coca-Cola, Asa Candler. On March 15, 2006 ASA was allowed to change its call sign back to ACEY, after the New Mexico fighter unit went defunct. Over the years, ASA's ICAO identifier changed from ASE to CAA to ACY to ASQ.. The company went public when the initial stock offering was completed in 1982.
The first of a fleet of Embraer Bandeirante twin-engined turboprop light airliners was delivered to ASA in December 1980. On April 1, 1983 the company acquired Southeastern Airlines. About a year later, in 1984, ASA joined the Delta Connection Program as one of the first regional partners. After only a few years as a true regional airline, the company was named 'Regional Airline of the Year' by Air Transport World in January 1987.
ASA initiated jet service with introduction of BAe 146 aircraft in 1995. Two years later, the company began using the Canadair Regional Jet (CRJ) for service from its Atlanta hub. CRJ service from the Dallas/Fort Worth hub began in 2000.
On September 8, 1998 the company was honored as one of the global aviation and aerospace industry's best managed companies by Aviation Week and Space Technology magazine.
Delta Air Lines acquired the company on March 22, 1999, increasing its stake in Atlantic Southeast Airlines from 28% to 100%, and operations began on May 11 of that year. In 2000, Comair, a Delta Connection partner, joined ASA in announcing industry's largest regional jet order. Also in 2000, ASA went international with flights to Toronto, Canada, from Atlanta.
In 2001, President Skip Barnette was named Regional Airline Executive of the year by the 2000 Commuter/Regional Airline News. Near the end of 2001, ASA carried the 2002 Olympic Flame between Miami, Florida and Mobile, Alabama, as part of Delta's sponsorship of the 2002 Olympic Winter Games in Salt Lake City.
In 2002, ASA received and began using its first Delta Connection 70-seat CRJ700 aircraft. All previous CRJs were CRJ200 models, which only offered 50 seats. Also in 2002, ASA began service to its 100th airport: Cincinnati/Northern Kentucky International Airport in Cincinnati, Ohio. By June 2003, ASA had received its 100th CRJ. In 2004, a special-edition CRJ700 was delivered to ASA to celebrate its 25th anniversary of passenger service.