MOSCOW, MAY 1 -- Crowds of marchers poured onto Red Square for a traditional May 1 demonstration today that stressed the themes of Soviet leader Mikhail Gorbachev's campaign for "restructuring."

Carrying banners and slogans, balloons and artificial flowers, tens of thousands of people streamed past the Lenin mausoleum, where Gorbachev and other members of the Soviet leadership stood smiling and waving during the 2 1/2-hour display.

The tone for the day's celebrations was set by an editorial today in the Communist Party newspaper Pravda, which hailed the "atmosphere of revolutionary renewal" in Soviet society.

"Antiquated stereotypes are being broken up, so is the braking mechanism. People are learning to think and act in a new way," the newspaper said.

Slogans touting similar themes were carried by local Moscow party activists through the colorful and noisy parade today, as different regions and industries sponsored floats, topped with pledges to improve output and quality. According to the news agency Tass, this year's parade featured new samples of light fabrics and a new truck, produced by Moscow's giant Zil factory.

Other topics this year included attacks on the Strategic Defense Initiative, the U.S. antimissile defense program, and appeals for an arms agreement in Geneva.

One float carried a display honoring American scientist Charles Hyder, whose six-month-long hunger strike for nuclear disarmament in front of the White House has been followed closely by the media here and has turned him into a national hero.