BURBANK, Calif. (AP) _ Lockheed Corp. says it will phase out all operations at the site where ''Rosie the Riveter'' cranked out 30,000 warplanes in World War II and the ''Skunk Works'' designed America's most secret aircraft.

The nation's sixth-largest military contractor said the changes would help it adjust to an expected decline in defense spending.

''We will take advantage of this situation to streamline our aircraft operations and enhance profitability,'' said Chairman Donald Tellep.

Lockheed, which has built planes in Burbank since 1928, said Tuesday it will move its aerospace division to Marietta, Ga., outside Atlanta.

The move to Georgia, where Lockheed already builds and services cargo planes at a government-owned facility, will cut costs substantially, Tellep said.

The Skunk Works research unit, where spy planes and the stealth fighter were developed, will become a separate subsidiary and gradually move from the 320-acre Burbank site to Palmdale, in the desert 50 miles north of Los Angeles.

The moves mean more bad news for the aerospace industry in California. State Rep. George Miller said last week the state could lost 200,000 defense- related jobs by 1995.

McDonnell Douglas Corp.'s Douglas Aircraft is eliminating 3,000 jobs, most of them in Long Beach. Lockheed said recently it would lay off 2,000 workers in Burbank, Palmdale and Santa Clarita, along with 750 in Marietta.

Lockheed spokesman Ron Meder said the company will finish moving all operations out of Burbank by the mid-1990s.

Corporate headquarters will remain in Calabasas, Calif.

Lockheed's profits plummeted from $624 million in 1988 to $2 million in 1989 last year, and the company faces tough times as easing world tensions pressure the government to cut defense spending.

Tellep said Lockheed would continue to develop its new P-7 submarine- hunting plane in California but will build it in Georgia.

Lockheed also will build the Advanced Tactical Fighter in Georgia if it wins the competition for one of the last major aerospace defense contracts in this century. A Lockheed-led team is competing with one led by Northrop Corp., and a decision is expected next year.

Securities analysts said the move may help Lockheed curry support for its ATF bid from Sen. Sam Nunn, the powerful Georgia Democrat who heads the Senate Armed Services Committee.

Lockheed's operations in Burbank date back to 1928. It produced 30,000 fighters and bombers there during World War II. The Skunk Works designed secret aircraft such as the U-2 and SR-71 spy planes and the stealth fighter.

Lockheed's aerospace division has come on hard times of late, with four major military plane programs ended or about to end: the C-5 cargo plane, the P-3 antisubmarine patrol plane, the TR-1 high-altitude reconnaisance plane and the F-117A stealth fighter.

Employment at the Marietta plant has fallen from 20,000 workers two years ago to about 9,000. Lockheed said the shift of the aerospace division wouldn't lead to any immediate surge in employment in Marietta because no new aircraft production is scheduled until the mid-1990s.