Delta formed a joint venture (and even acquired a stake in) Korean Air and sees Seoul-Incheon now as its connecting hub to Asia.
They’ve wanted to be able to move their entire Tokyo operation to the close-in Haneda airport. That’s because they see Tokyo now as a destination rather than a connecting point. They’ve argued to the DOT in the past that if they don’t get enough slots at Haneda to run their own set of flights, that no U.S. airline should get to fly to Haneda. It was an aggressive position, but it largely worked.