While the United States continued to defy China by sending military planes into the zone unannounced, administration officials said they had made the decision to urge civilian planes to adhere to Beijing’s new rules in part because they worried about an unintended confrontation.

Although the officials made clear that the administration rejects China’s unilateral declaration of control of the airspace over a large area of the East China Sea, the guidance to the airlines could be interpreted in the region as a concession in the battle of wills with China…

The decision contrasted with that of Japan’s government this week, when it asked several Japanese airlines, which were voluntarily following China’s rules, to stop, apparently out of fear that complying with the rules would add legitimacy to Chinese claims to islands that sit below the now contested airspace. China’s newly declared zone, experts say, is intended mainly to whittle away at Japan’s hold on the islands, which it has long administered.