Alaska Airlines closed its $1 billion purchase of Hawaiian Airlines on Wednesday, a day after the federal government removed the last major regulatory obstacle to the deal. Alaska will also assume about $900 million in Hawaiian debt.

Alaska Air Group completed the acquisition of Hawaiian Holdings on September 18, the company announced, “marking the beginning of a partnership” that will maintain the Alaska Airlines, Hawaiian Airlines, and Horizon Air brands as separate entities.

Things are about to change for Alaska and Hawaiian Airlines customers. On Wednesday, Alaska Airlines acquired Hawaiian Airlines in a historic merger. The acquisition is the largest merger between U.S.