30天內您說可以再回美國。 請問我查到有人說隻能走陸路， 不能飛機回美， 是這樣嗎？
-No such limitation. But some airlines may not understand this rule and thus, may not allow you to board the plane. So, you may print out the USCIS or CBP docuements about this rule.
See these websites:
出境的時候也不能交回I-94 （半年有效）卡，對嗎？
-Correct. Show this I-94 to the CPB officer when you return to US from Canada.
