父母用AP回国等绿卡，现在绿卡批了，他们想过来拿绿卡和办re-entry permit. 现在给他们买机票，有几个问题请教大家。
2小时底特律转机（同家航空公司）够吗？他们只有随身行李。
他们入关时可以走US Citizens and Permanent Residents关口吗？
-Probaly no because they don't have the green card in hand. They need to show the AP to the IO. You had better write a letter for your parents addressing that their I-485 was approved during their travel. Thus, they can just submit the letter to the IO at the port of entry. They had better also provide the copy of the I-485 approval notice to the IO (not have to if they don't have it in hand).
如果被问来美国原因，可以说绿卡批了，开始慢慢搬家到美国吗？-Not need to explain anything. But they need to return to US before the AP expires.
多谢！
