Boeing 737-790 aircraft belonging to Alaska Airlines is seen flying at Anchorage Ted Stevens International Airport in Anchorage, Alaska, United States on July 2, 2024.Alaska Airlines and Hawaiian Airlines can go through with their planned merger, but they must maintain the value of their airline reward systems and preserve several key routes, the U.S. Department of Transportation said Tuesday.The two carriers' $1.9 billion merger agreement cleared the U.S. Justice Department's review last month. That put it ...