Several countries ignore China's air space claims over disputed island

Reuters/NY Times:

Japanese and South Korean military aircraft flew through disputed air space over the East China Sea without informing China, officials said on Thursday, challenging a new Chinese air defense zone that has increased regional tensions and sparked concerns of an unintended clash.

The move came after Tokyo's close ally Washington defied China's demand that airplanes flying through its unilaterally announced zone identify themselves to Chinese authorities, flying two unarmed B-52 bombers over the islands on Tuesday without informing Beijing.

Tensions have ratcheted up since Beijing's weekend announcement of the zone that includes the skies over islands at the heart of a feud between Japan and China, and its demand that planes flying in the area first notify Chinese authorities.

Japan and the United States have sharply criticized the move, which some experts said was aimed not only at chipping away at Tokyo's control of the islands, known as the Senkaku in Japan and the Diaoyu in China, but also at challenging U.S. dominance in the region.

The United States does not take a position on the sovereignty of the islands but recognizes Tokyo's administrative control and has assured Japan that the U.S.-Japan security pact covers them.
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At this point it looks like the Chinese are being challenged on their claim in more than a rhetorical fashion.  They have responded to the challenge by sending their refurbished aircraft carrier to the area.  I don't view it as athreat to US fighter planes stationed in Japan,