Alaska Air Group, the parent company of Alaska Airlines, plans to invest $2.3bn to improve infrastructure across four airports in the US.

The company plans to invest in airports in Seattle, Portland, San Francisco and Los Angeles.

At Seattle-Tacoma International Airport (SEA), the group plans to kick off the first phase of a major terminal project this summer.

The first phase of the project will see the addition of an area of nearly 20,000ft² to accommodate employee offices and ticket counter space in the undeveloped space between the ticketing and bag claim levels and the airport’s sky bridges.

The company will also invest in San Francisco International Airport (SFO), where it plans to relocate its entire operation in 2024.

At SFO, Alaska Airlines plans to shift its check-in ticket counter, gates and baggage services from Terminal 2 to the Harvey Milk Terminal 1.

The move is expected to benefit the company as the new gates will result in shorter taxi times and faster access to the runways.

In Portland International Airport, the group will partly fund the $1.6bn terminal modernisation project, which is being carried out by the Port of Portland.

The project will expand lobby space and streamline the check-in process, as well as create additional dining and retail options. The company will also invest in the airport’s Concourse B and lounge upgrades.

Finally, at Los Angeles International Airport (LAX), Alaska Air Group will make an investment of $230m to overhaul the gate areas in Terminal 6. The overhaul will include new carpet, signage, lighting and seating with power outlets.

With these investments, Alaska Airlines passengers will have access to more gates, lounges and lobbies.