Dec 4 (Reuters) - Shares of Hawaiian Holdings, the parent of Hawaiian Airlines, nearly tripled on Monday after Alaska Air Group agreed to acquire it for $1.9 billion, including debt.

Hawaiian shares were trading at $13.40 in morning trade, below Alaska's offer price of $18 per share made public on Sunday, with some analysts saying regulatory approval was far from certain.

The company's shares had taken a beating in recent months due to the impact of the Maui wildfires, high fuel costs and jet engine recall issues at some of its Airbus SE planes. Its shares have fallen 52.6% so far this year.

Hawaiian presently has a negative price-to-earnings (PE) ratio of 1.5, reflecting losses, compared to a positive forward 12 months PE ratio of 8.2 for Alaska Air, according to LSEG.

Alaska and Hawaiian said on Sunday the deal, valued at $929.4 million on an equity basis, will expand their networks and offer more choices to passengers.

"This transaction makes good common sense for both airlines," TD Cowen analyst Helane Becker wrote in a note.

The deal will enable Alaska to grow in the lucrative Asia Pacific market, while Hawaiian customers can travel non-stop to the U.S. mainland, Becker added.

However, regulatory resistance to the merger is a possibility. Under a hawkish Biden administration, the U.S. Justice Department had filed a lawsuit in March to stop JetBlue from buying Spirit Airlines, saying the planned merger "would put travel out of reach for many cost-conscious travelers".

JetBlue shares pared losses from premarket to trade flat, while Spirit shares were up 6.5% on Monday.

Alaska Air's CEO Ben Minicucci in an interview on Sunday expressed confidence that regulators would approve the deal by the end of 2024 because the two airlines have just 12 overlapping routes out of the 1,400 flights they collectively operate.

Shares of Seattle-based Alaska Air were down 17.6%.

(Reporting by Ananta Agarwal in Bengaluru; Editing by Krishna Chandra Eluri and Shinjini Ganguli)