Japanese permission is needed before Taiwan activists can proceed with plans to make a helicopter landing on the disputed Diaoyu Islands in the East China Sea on Friday, aviation authorities in Taipei said yesterday. The activists, led by New Party National Assembly deputy Feng Hu-hsiang , want to time the landing to coincide with the 51st anniversary of the end of Japanese rule over Taiwan. If two rented helicopters cannot land on the islands, the activists want to drop the Nationalist Chinese flag as a demonstration of sovereignty. Chang Kuo-cheng , acting director-general of Taiwan's Civil Aeronautics Administration, said his agency had yet to decide whether to permit the planned expedition. 'We haven't replied to anything yet,' he said. 'Someone has said we didn't allow them. That's completely unfounded.' Mr Chang said he was waiting for a 'higher authority' to make the decision. But Japanese authorities had to be notified of any trip to the islands as Japanese air traffic controllers on nearby Okinawa were responsible for monitoring the Diaoyu airspace, he said. While Taipei claimed sovereignty over the islands, Okinawa's role in monitoring the airspace over them was mandated by the International Civil Aviation Organisation, Mr Chang said. No response had been received from Okinawa, he said. Before the US Government handed Okinawa back to Japan in 1972, US military authorities had recognised the airspace over the Diaoyu Islands as being under Taiwan's control, he said. Washington never changed that policy, but it later incorporated the airspace over the islands into its own air defence zone, he said. That zone was transferred to Japanese military authorities when Okinawa was returned to Japan. Mr Chang also warned the activists that dropping items out of a helicopter was illegal under Taiwan law. It carried penalties ranging from a fine up to revocation of the helicopter pilot's licence. But Mr Feng took issue with Mr Chang and his warning. 'If the Diaoyu Islands are Taiwan's territory, the airspace over them is certainly ours,' Mr Feng said. He said lawmakers were prepared to demand the resignation of officials who refused to respect the people's wishes.