Delta Air Lines said it will end its code-share partnership with Alaska Airlines that allowed the carriers to sell each other's flights.
Atlanta-based Delta, which said it has more than tripled its own flights at its Seattle hub since 2013, said the code-share marketing arrangement with Alaska will end May 1, 2017.
"Delta and Alaska today codeshare on only a small number of flights as Delta's growth in Seattle has reduced the need for codeshare flying," Delta said. The ailrine "will continue its commitment of investment and growth in the Pacific Northwest" following the decision.
Alaska, meanwhile, is focusing on its recently-closed acquisition of Virgin America.
Delta and Alaska in 2008 announced an expanded code-share marketing alliance, with the CEOs of Delta and Alaska Airlines announcing the deal together.
But in recent years, the partnership has become fraught with competitive tension as Delta built a hub in Seattle that goes head-to-head against Alaska Airlines' main hub there.
As each carrier increasingly defends its own turf, the code-share arrangement has been shrinking in significance.
Once the code-share agreement is over, passengers on Alaska Airlines flights will no longer be able to earn Delta miles, or vice versa. And Delta elite frequent fliers will no longer receive their benefits when flying Alaska Airlines starting May 1.
Still remaining between the two carriers is a standard industry arrangement known as an interline agreement allowing the airlines to connect baggage and tickets on itineraries with flights booked on both airlines.