San Francisco International Airport today had good news and bad news for holiday travelers: security will be further tightened and parking will be cheaper.

Even though there will be fewer people than in the past, lines probably will be longer and travelers should arrive at the airport three hours before departure.

SFO spokesman Ron Wilson said today the airport increased its California National Guard presence by 25 percent, to 140 armed soldiers, under orders from the Federal Aviation Administration.

The soldiers will patrol garages and the perimeter of the airport as well as the terminals, Wilson said. In addition, there will be more roving patrols of San Francisco police officers.

The added security, which he said will be beefed up on a daily basis, is needed because "airports like ours were never designed for this kind of security."

He said inspection of baggage will be tighter and lines will be longer, so much so that the airport is installing chairs for people to rest on while they're waiting.

Wilson advised arriving at the airport three hours before scheduled departure time.

Wilson also announced a "parking lot sale" to drum up business for the holiday season.

Parking in short-term garages, starting today, will be $24 a day until the day after Thanksgiving. The former rate was $28 for the first day and $35 for each succeeding day. Long-term parking will be $12 a day, down from $15, through Nov. 23.

Asked why the discount, Wilson said frankly, "Because we need the money."

With airline traffic down 20 percent since the Sept. 11 terror attacks, Wilson said SFO is expecting a revenue loss of $100 million through the third quarter of the year.

The airport is giving $1.5 million a month in rent discounts to airport concessionaires, whose business is down by 40 to 70 percent, he said.

Wilson said he expects air traffic to be 8 to 12 percent lower than usual on the Thanksgiving holiday, normally the airport's busiest time. He said about 105,000 people are expected to pass through the airport, which is similar to the number on a normal day before Sept. 11 and nowhere close to typical Thanksgiving traffic.

Noting stricter baggage check procedures, Wilson used an airport press conference to display some of the 1,600 pounds of confiscated items. They included chopsticks, cuticle scissors, beer can openers, wooden matches and aerosol sprays.

He said airport officials were still in the dark about how the changeover from privately hired security guards to federally employed guards would work at SFO. Under legislation hammered out by Congress that President Bush said he will sign as early as Monday, security of U.S. airports will be placed under control of the federal government.

Currently, three firms -- Globe, Argenbright and ITS -- employ some 1,100 security personnel at the airport. Wilson said the Airport Commission has not addressed how the changeover will be handled.