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.

The merger between Alaska Airlines and Hawaiian Airlines is official, making it possible to share loyalty benefits between both carriers.

The U.S. Transportation Department said on Tuesday it had agreed to allow Alaska Airlines to close on its $1.9 billion acquisition of Hawaiian Airlines, after the carriers agreed to maintain key Hawaiian routes and adopt consumer protections.