Southwest Airlines (WN, Dallas Love Field) will lease a total of ten slot pairs at New York La Guardia and Washington National from Alaska Airlines for a period of ten years, commencing in October 2018, Alaska Air Group Chief Commercial Officer Andrew Harrison said during a quarterly earnings call on April 24.

"We've received approval from the Department of Justice and have executed an agreement with Southwest, under which Southwest will lease out 12 within perimeter slots at La Guardia and our eight within perimeter slots at DCA. The lease, which commences this October, enables us to monetize these valuable slots while reallocating our flying from DCA and La Guardia into Dallas Love Field, to more strategic and profitable opportunities of the West Coast," Harrison said.

Under the terms of the lease, the slots may return to Alaska Airlines in 2028. The value of the transaction was not disclosed.

Southwest Airlines has told The Dallas Morning News that it will announce the details of its new services out of La Guardia and Washington National in the coming weeks.

According to the ch-aviation capacity module, Southwest Airlines currently operates a total of 212 weekly departures out of La Guardia, while Alaska Airlines operates only 25 weekly departures out of the airport. Out of Washington National, Southwest Airlines operates 291 weekly departures and Alaska Airlines 55.

Following the commencement of the lease in October, Alaska Airlines will terminate its services out of each of La Guardia and Washington National to Dallas Love Field. It currently operates a total 120 weekly departures out of the Texan airport, where it has two gates since its acquisition of Virgin America.