U.S. antitrust regulators say Southwest's purchase of AirTran Airways isn't likely to hurt airline competition, clearing the way for the deal to close next week.

The Justice Department said Tuesday that the airlines overlap on some nonstop routes, but it decided not to challenge the deal because there is room for new competitors in those cities.

Southwest, based in Dallas, plans to close the $1.4 billion purchase on Monday. The deal will immediately increase Southwest's size by one-fourth and give it an opening in Atlanta and service to Mexico and the Caribbean.

Tags: Southwest Airlines, Airtran Airways