Alaska Air Group has agreed to buy rival Hawaiian Airlines

in a $1.9 billion deal, setting up another potential regulatory battle in the second proposed airline merger in less than two years.

Alaska would pay $18 a share for Hawaiian and would take on $900 million of its debt, the companies said Sunday. Shares of Hawaiian Airlines closed on Friday at $4.86, giving the company a market capitalization of about $250 million. They're down nearly 53% this year.

The airline has struggled with challenges including the Maui wildfires, increased competition from Southwest Airlines

, which has ramped up service in Hawaii in recent years, and a lagging recovery of travel to and from Asia after the pandemic. Hawaiian has posted net losses in all but one quarter since the start of 2020, while Alaska and other carriers have returned to more solid financial footing as the pandemic waned.