United Airlines' service from Paine Field in Everett, Washington, will begin March 31, the carrier said Monday.

United had already announced its intention to fly from the airport north of Seattle, but it had not yet set a start date for its planned routes to Denver and San Francisco.

United will become the second carrier to offer flights from Paine Field, which has been without commercial service for decades. Alaska Airlines will be the first airline to resume commercial passenger service from the airport, launching 18 daily round-trip flights to eight West Coast airports on Feb. 11. Southwest also had announced plans to begin flying from Everett, but eventually abandoned that effort and transferred its Paine Field flight slots to Alaska Airlines.

As for United, it will run a schedule of six daily round-trip flights from Everett. Four will go to San Francisco and two to Denver. All will be operated by United Express affiliates on 76-seat Embraer E175 jets.

“We are excited to offer our Seattle and Northwest Washington area travelers new opportunities to easily access our hubs in Denver and San Francisco,” Ankit Gupta, United’s vice president of Domestic Network Planning, said in a statement.

Paine Field already hosts a busy flight schedule, but that’s not from regular airline service. Instead, the facility is adjacent to Boeing’s largest assembly line, where the U.S. jetmaker performs final assembly on its 747, 767, 777 and 787 widebody aircraft.

Boeing’s large aircraft keep a heavy flight schedule at the airport, which also hosts some private general aviation flying.

But in May 2017, Alaska Airlines announced its intention to begin flying from Everett, which is about 25 miles north of downtown Seattle.

Seattle-based Alaska Airlines already operates its busy hub at the fast-growing Seattle-Tacoma International Airport that sits about 15 miles south of the city.

When it announced its plans for Everett, it touted the move as a way to expand its reach into the northern stretch of Seattle’s metro area, where travelers can face daunting traffic on Interstate 5 to get to Seattle-Tacoma.

United also flies from Seattle-Tacoma, where it offers up to 40 daily flights to its U.S. hubs.

TODAY IN THE SKY:Photo tour: Behind the scenes at the Boeing factory

IN PHOTOS: Behind the scenes at the Boeing Field flight line