The Dallas-based carrier returned the slots to United Airlines, which assumed control of them through its 2010 merger with Continental Airlines. Continental had traded the pairs with AirTran Airways in exchange for slots at the then newly slot-restricted Newark airport in 2009. Southwest acquired AirTran in 2010.
The trade was nullified with the US Federal Aviation Administration’s decision in April to lift slot restrictions at Newark from 30 October. This eliminated the collateral that Southwest provided United under the terms of the deal.
“While it was not ideal for Southwest Airlines, it was an agreement that we agreed to in the lease,” says a spokesman for the airline.
Southwest now has 42 slot pairs at Washington National, putting them just ahead of United with 41 pairs and well behind Delta Air Lines with 54 pairs, FlightGlobal schedules data shows. American Airlines has the largest slot portfolio at the airport operating up to 251 daily flights.