The state is spending more than $20 million to improve four Hawaii airports.

About half of the money, $9.7 million, will pay for the replacement of some 30 escalators at Honolulu Airport, where a majority are more than two decades old, the Governor's Office said in a news release this week. The work is scheduled to be completed in June 2010.

Lihue Airport on Kauai will get $3.1 million to expand its parking lot by 422 stalls for a total of 1,425 spaces. The project also will add an employee parking area with electronic gates and a taxi lane.

On the Big Island, Hilo Airport's parking lot will grow by 427 stalls to 1,305. The $3.2 million project also includes an employee parking area, a pedestrian walkway and lighting and landscaping work.

At Kona Airport, the state will use another $3.2 million for an interim commuter air terminal with lounges, offices and baggage storage areas.

All neighbor island projects are scheduled to be finished in December 2009.

Maui's Kahului Airport, meanwhile, has been equipped with a more efficient passenger processing system in which check-in counters are used by multiple airlines.