Alaska Airlines has agreed to acquire its rival Hawaiian Airlines in a deal valued at about $1.9 billion, as the companies make a push to expand along the West Coast.

The purchase values Hawaiian Airlines at $18 per share, and includes the inheritance of $900 million of the company’s debt, according to a news release Sunday. Shares of Hawaiian Airlines closed on Friday at $4.86, giving the company a market cap of about $250 million.

The transaction is expected to close in the next year or 18 months. The combined company will be based in Seattle, where Alaska Airlines is headquartered, and led by its CEO, Ben Minicucci.

The two airlines said they will aim to “maintain” each of their brand identities but operate under a single platform, combining into a 365-airplane fleet covering 138 destinations.

“With the additional scale and resources that this transaction with Alaska Airlines brings, we will be able to accelerate investments in our guest experience and technology, while maintaining the Hawaiian Airlines brand,” Peter Ingram, CEO of Hawaiian Airlines, said in the release.

The combination will allow Alaska Airlines to triple nonstop or one-stop flights from the Hawaiian islands to destinations throughout North America.

Alaska Airlines said the deal should bolster earnings within the next two years with at least $235 million of expected “run-rate synergies.”

“We are fully committed to investing in the communities of Hawai’i and maintaining robust Neighbor Island service that Hawaiian Airlines travelers have come to expect,” Minicucci said in the statement.