这里面有个缘故：虽然美国政策中预先通知原则仅适用于飞往美国空域的飞行器，但实际操作中美方却要求途经其防空识别区的所有航班无论目的地是哪里都要预先通报。
There is a reason for this: Although the prior-notification rule in American policy applies only to aircraft headed for US national airspace, in practice the US demands advance notification of all flights through its ADIZ, regardless of their intended destination.