China has suggested it will create more air defense zones, which worries Southeast Asian nations that have territorial disputes with China.
Regional ties are at a new low since China's unilateral announcement, but China may be willing to endure short-term displeasure for long-term gains.
China's decision to send in warplanes is likely a bid to enforce the new air-defense zone after the US, Japan and South Korea all flew planes through without any response.
Beijing wants to change the status quo in the East China Sea. US officials think it unlikely that China will challenge military flights.