Tokyo's new international airport survived its first day of air traffic without serious incident yesterday despite its opponent's sporadic attempts to disrupt operations.

A few flights were delayed, but at the end of the day authorities believed they were over the rough spots and thought that the beleaguered airport would continue to function normally.

For several hours, officials said, the anti-airport coalition tried to interfere by beaming radio signals intended to obstruct communications between the airport control tower and pilots of incoming planes.

But the jamming signals were too feeble to cause serious interference and all planes landed safely.

Masatsu Yoshinaga, pilot of the first passenger aircraft, said that during his approach he noticed two or three instances of radio interference. They did not worry him because his visibility was good and there were no other planes in sight, he said.

After Saturday night's violence, which included two large-scale firebomb attacks, the radicals and farmers trying to block the airport's operations were largely reduced to tilting at windmills.

They used acetylene torches to cut down a steel pylon holding power lines. That knocked out electric service for about 19,000 homes near the airport in suburban Narita, but the airport itself was unaffected.

They also chopped down two trees that fell across an access road in an apparent attempt to obstruct trucks carrying airline equipment to Narita from the old international airport at Haneda. The trees were quickly cleared away.

And they flew baloons and kites in the path of the runway shortly before the first plane arrived from Los Angeles Sunday morning. But they were too low to interfere with the landing aircraft.

The number of opposition demonstrators dwindled from a peak of about 15,000 to 200 by late yesterday afternoon.

Authorities were not discounting the possibility of continued guerrilla tactics, like the severing of microwave cables Saturday that knocked out the radar and voice communications systems at Haneda airport. But the officials hoped that the successful landings of a score of passenger and cargo aircraft yesterday would dissipate the opponent's persistence.

The radicals and some of the farmers in the movement, however, threatened to continue with assaults on water and power supplies.

The opening-day traffic was a success for the government of Prime Minister Takeo Fukuda, who had said that Japan's international prestige was at stake. Fukuda had been severely embarrassed when the airport's March 30 opening had to be postponed after radicals broke into the control tower and heavily damaged equipment.