Allegiant will add Jackson Hole, Wyo.; Key West; and Portland, Ore., to its route map.
The discount carrier's service from Portland will begin in April with flights to the central California coastal destination of Santa Maria. Flights to Monterey, Calif., and Idaho Falls, Idaho, will follow in May.
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Allegiant flights from Jackson Hole launch in June with service to Los Angeles, Phoenix Mesa, Las Vegas and Reno.
The carrier's service from Key West also begins in June, with flights to Nashville and Sanford, Fla., in the northern Orlando area.
Those nine routes are among 21 new city pairs Allegiant announced Tuesday, including eight routes that were delayed in 2020 due to the Covid-19 pandemic.
"Today, travelers are seeking destinations that allow them the chance to recreate in a safe way, usually outdoors," said Drew Wells, Allegiant's vice president of revenue and planning. "The three cities we're adding to our network -- Key West, Portland and Jackson Hole -- are gateways to some of the United States' most scenic destinations, including national parks and other outdoor attractions that are in high demand."