Airlines from China and Japan have cut or delayed flights between the two countries as tensions mount between the region's two largest economies over a dispute about an uninhabited group of islands in the East China Sea.
China Eastern Airlines said it would delay the launch of a new route between Shanghai and Sendai, which was scheduled to start on October 18, due to insufficient passenger demand.
A China Eastern spokesman declined to say if the delay was related to the growing tension between the two sides, but he warned the situation could deteriorate.
"Other flights (to Japan) are now operating as normal, but we expect those flights will be affected too," the spokesman said.
Japan Airlines said it would reduce daily flights to China, excluding Hong Kong, by three to 10 until October 27, while the Nikkei business daily said JAL had about 12,000 cancellations to China on flights between September and November, including 5,500 seats cancelled flying out of Japan and 6,500 seats cancelled from China.
"JAL doesn't see a very large impact on earnings from this," a JAL spokesman said. "China-Japan flights make up little more than 10 percent of international flight sales, and the impact on overall profits is small."
New reservations volume had dropped and JAL would gauge demand in October and decide whether to extend the flight cuts beyond October 27, Takamoto added.
All Nippon Airways said it was monitoring the situation closely.
"We are doing all we can to avoid cutting flights, but an announcement could come at any time, given the level of cancellations," an ANA spokesman said.
Street protests in China have forced some Japanese firms to suspend operations in that country, and the share prices of Japanese firms with exposure to China have tumbled.
Japan has controlled the disputed rocky islets since 1895 - except during the 1945-1972 US post-war occupation of Okinawa - and calls them the Senkakus. China maintains it has an older claim and calls them the Diaoyu islands.