The City of Dallas, owner and operator of Dallas Love Field airport, has filed a lawsuit in a US federal court seeking a declaratory judgment to determine which airlines are entitled to use which gate slots at the metropolitan airport.

“This lawsuit will allow all of the interested parties to put forth their positions in a structured setting so that the federal court can properly weigh their rights and obligations and thereafter allocate the gates in accordance with the law,” Dallas City Attorney Warren Ernst said.

The municipality is currently embroiled in the midst of a dispute between Delta Air Lines (DL, Atlanta Hartsfield Jackson) and Southwest Airlines (WN, Dallas Love Field) over the former's continued access to Dallas Love Field. Delta's Love Field services could end on July 6 when a temporary agreement with Southwest allowing Delta to use two gates, subleased to the Texan LCC by United Airlines (UA, Chicago O'Hare), expires.

Delta has struggled to retain its Love Field rights since American Airlines (AA, Dallas/Fort Worth), from which it had previously leased gates, disposed of its pair of gates to Virgin America (San Francisco) as part of anti-trust proceedings last year.

The Department of Transportation (DOT) has also waded into the dispute issuing guidance to the City of Dallas to the effect that given Love Field's unique circumstances, it is legally obligated to accommodate all air carriers seeking to provide service there.

"It is DOT's view that making reasonable efforts to accommodate new entrants or other carriers seeking expansion at Love Field, as described in our December 17 letter, follows the airport's obligation to make the airport available on 'reasonable conditions' and 'without unjust discrimination.' Likewise, efforts to accommodate new entrants or other carriers seeking expansion at Love Field ensure that the airport has not given an 'exclusive right' to a carrier at the airport," the DOT's General Counsel Kathryn Thomson said in a letter to the City of Dallas last week.

Understandably, Southwest has rejected the DOT's guidance claiming it violates the LCC's legal and contractual rights while supporting the City of Dallas in its bid to manage Love Field in accordance with its obligations under airline leases and the Wright Amendment Reform Act (WARA). In February, Southwest filed its own legal petition disputing the DOT's guidance.

"The lawsuit filed by the City of Dallas allows the City and Southwest to ask the court to properly interpret applicable law as well as the contractual agreements entered into by the City and Southwest relating to Love Field, which clearly give Southwest the right to expand upon and maximize the usage of its leased gates in the best interest of the citizens of Dallas," Southwest said.

Love Field's other operators, Virgin America and partner SeaPort Airlines (Portland International), have also come out in support of Southwest and the City.

In the lawsuit, Dallas contends that the WARA, the five-party agreement (among Dallas, Fort Worth, Dallas/Fort Worth, Southwest Airlines, American Airlines) and the City’s leases with other airlines using the airport, conflict with and take precedence over directives from the US Department of Transportation and the Federal Aviation Administration (FAA) and the demands from other airlines seeking to use the gates.

Aside from the Southwest/Delta dispute, Dallas' lawsuit also claims American Airlines intends to resume Love Field operations despite relinquishing its two gates to Virgin America last year.

For its part, Delta has threatened to file its own lawsuit against Dallas accusing the airport of 'anti-competitive' and 'collusive' behaviour aimed at stifling competition.

"Unless the city can live up to its obligation under federal law and accommodate Delta’s five daily flights to Atlanta Hartsfield Jackson, Delta will have no choice but to file for emergency injunctive relief to avoid disrupting thousands of passengers,” it said.

Beginning August 9, Southwest plans to fully utilize its eighteen Love Field gates offering 180 flights a day or ten flights a day per gate.