Southwest Airlines is challenging Delta Air Lines’ decision to remain at Dallas Love Field past July 6 based on permission from a Department of Transportation (DOT) letter.
Delta was supposed to lost access to its slot at the Dallas airport, which was leased from American Airlines, in October 2014 when American Airlines transferred its gates at the airport to Virgin America as part of its merger settlement with the US Department of Justice.
Delta managed to extend an agreement with United Airlines to maintain its Dallas Love Field operations through to July 6. However, DOT's General Counsel, Kathryn Thomson, announced in December last year that any airline currently operating out of Dallas Love Field could maintain its operations out of the airport “as long as the carrier continues to operate the accommodated flights”.
Southwest has since filed a petition in a federal appeals court in Washington, DC to review the letter, seen as a directive, which it has labelled "arbitrary and capricious, an abuse of discretion, and otherwise not in accordance with law."
Southwest holds 16 out of Love Field's 20 available gates but needs the additional gates to offer daily nonstop flights to nine new cities and to increase coverage to existing destinations.