(Reuters) - Delta Air Lines Inc and Southwest Airlines Co have scheduled overlapping flights from identical gates at Love Field in Dallas, creating potential havoc for customers as a gate-sharing agreement between the carriers is set to expire and a court battle looms over slots at the airport.
Southwest, which holds 18 of 20 gates at the airport, agreed that Delta could use certain gates until July 6. Southwest plans to ramp up flights in August from Love Field, its headquarters, contingent upon regaining all takeoff and arrival slots from Delta.
However, Delta is selling tickets to Love Field through May 2016, a sticking point in a conflict that has drawn in city and federal officials.
On Friday, Delta threatened legal action against Dallas if the city did not accommodate its flights, saying inaction amounted to a failure of federal obligations and an assault on consumer choice that would result in "disrupting thousands of passengers," according to a Delta spokesman.
The airline cited a letter from the U.S. Department of Transportation on Monday that asked Dallas to foster competition by accommodating smaller players at the airport like Delta when possible.
Dallas had responded Wednesday by suing the federal agency for asking the city to violate a lease agreement with Southwest that is protected by federal statute. It also named the Federal Aviation Administration, Delta, Southwest and other airlines at Love Field as defendants.
Southwest has also threatened to sue Dallas if Delta stays past Aug. 9, the city's lawsuit said. Southwest said Thursday, DOT's "guidance not only violates Southwest's legal and contractual rights but would also reduce competition."
The spat is part of a larger fight for passengers in the Dallas market that has investors concerned that airlines will discount fares and hurt revenues because of a surge of flights from the city.
Delta has 45 daily flights from Dallas/Fort Worth International Airport (DFW) but wants a foothold at Love Field, which some travelers prefer for its renovated terminal and proximity to downtown Dallas. It operates five flights there and has petitioned to add eight more.
Customers who have booked Delta flights past July 6 may see changes to their plans and be routed through DFW if the Atlanta-based airline loses slots, creating short-term confusion, said Charlie Leocha, chairman of consumer advocacy group Travelers United.
"For Delta to schedule service when they don't even have a legitimate lease is just deceptive," he said.
(Reporting By Jeffrey Dastin in New York; Editing by Joseph White and Bernard Orr)