Directly from the DOJ:

Assistant Attorney General Bill Baer of the Department of Justice’s Antitrust Division. This settlement will disrupt the cozy relationships among the incumbent legacy carriers

Specifically, the settlement requires the companies to divest or transfer to low cost carrier purchasers approved by the department

By guaranteeing a bigger foothold for low-cost carriers at key U.S. airports, this settlement ensures airline passengers will see more competition on nonstop and connecting routes throughout the country

According to the DOJ, Delta need not apply.