另外, https://help.cbp.gov/app/answers/detail/a_id/752/~/how-to-record-departure- from-the-united-states-after-the-fact Delays beyond the traveler's control, such as cancelled or delayed flights, medical emergencies requiring a doctor's care, etc. are not considered unauthorized overstays, however, you will need to bring proof of the cause of your overstay next time you travel to the U.S. in order for it to be forgiven. For airline delays, ask the airline for a letter affirming the delay or a copy of your cancelled boarding pass.