I am going to Vietnam in June, come back in July, and my passport is expired in August (1 month and 10 days after the day I come back to the US). My visa to enter Vietnam is expired in September. United Airlines told me that my password has to be valid at least 1 month after my visa's expiration date. Is that right? I don't have enough time to request for new passport and visa now. Also, there is no where else that says that. All othe places say that I only need a valid visa to enter and exit Vietnam and a valid passport to enter US. Is this right? Thank you for your response.