请问美国是否有相关法律规定不允许无监护人陪同的未成年人单独入境？如果没有的话，下飞机后过海关会盘问得很严格吗？
PS：经常听到一些高中生独自出国走遍全世界的励志故事，不知是否有实际操作性？
-The airlines normally have such services. So contact the airlines. The parents need to write a letter to allow the airlines to bring their child to US. See the following websites:
https://help.cbp.gov/app/answers/detail/a_id/268/~/children---child-traveling-with-one-parent-or-someone-who-is-not-a-parent-or
http://www.americanairlines.cn/intl/cn/travelInformation/childtravel.jsp
PS：经常听到一些高中生独自出国走遍全世界的励志故事，不知是否有实际操作性？
-The airlines normally have such services. So contact the airlines. The parents need to write a letter to allow the airlines to bring their child to US. See the following websites:
https://help.cbp.gov/app/answers/detail/a_id/268/~/children---child-traveling-with-one-parent-or-someone-who-is-not-a-parent-or
http://www.americanairlines.cn/intl/cn/travelInformation/childtravel.jsp
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