A regional airline in Atlanta will soon end its run as a longtime Delta Connection carrier, a major shift for a company that built its business around Delta.

Atlanta-based ExpressJet, formerly known as Atlantic Southeast Airlines or ASA, will not fly for Delta after late 2018.

ExpressJet has long been the largest Delta Connection carrier flying out of Atlanta, and operates about 4.8 percent of the flights out of Hartsfield-Jackson International Airport.

It has recently added some flying for other carriers including American Airlines as American Eagle.

ExpressJet said it is “working to minimize employee reductions through natural attrition or transfer opportunities within our existing operations.”

To read more about why ExpressJet's contract with Delta is ending and what it means for passengers, get the full story on MyAJC.com.

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A timeline of ExpressJet's history... from its beginnings as Atlantic Southeast Airlines through the growth of ExpressJet and its merger with Atlantic Southeast Airlines:

1979

Atlantic Southeast Airlines acquires its first aircraft, a DeHavilland Twin Otter; opens a maintenance base in Columbus, Ga., and makes its first flight.

1982

Atlantic Southeast makes its initial public stock offering.

1983

Atlantic Southeast acquires the assets of Southeastern Airways.

1984

Atlantic Southeast becomes the first Delta Connection carrier.

1993

Bar Harbor, Rocky Mountain Airways and Britt Airways consolidate operations to form Continental Express as a single corporate entity operating under the Britt Airways certificate; the airline that would become ExpressJet is formed.

1995

Atlantic Southeast receives its first jet.

1999

Delta acquires Atlantic Southeast Airlines.

2005

Delta reaches an agreement to sell Atlantic Southeast to SkyWest, Inc.

2007

ExpressJet launches branded operations to 24 cities and begins operations as Delta Connection out of Los Angeles.

2008

Atlantic Southeast opens an Atlanta hangar, “A-Tech Center,” to perform scheduled overnight maintenance.

2009

ExpressJet begins flying as United Express.

2010

Atlantic Southeast acquires ExpressJet Holdings, Inc., parent company of ExpressJet Airlines, and announces plans to merge the two airlines.

2011

Atlantic Southeast and ExpressJet achieve single operating certificate status from the FAA and form the new ExpressJet.

2012

ExpressJet announces a new contract with American Airlines to fly as American Eagle beginning in 2013.

Aug. 9, 2017

ExpressJet and Delta announce plans to end their contract in late 2018.

Source: ExpressJet.com

Atlanta-based ExpressJet, formerly known as Atlantic Southeast Airlines or ASA, will not fly for Delta after late 2018.