What is an international flight when there is a US connection? (Dulles)
 

Boston-Dulles-Buenos Aires. I understand luggage goes from Boston-Argentina without re-taking possession of it (all flights on United). Does one need to get to Logan/Boston with extra time as with any international flight? Does passenger need to do anything special at Dulles other than get on the plane since that is the actual international flight? Thanks.

You don't need to do anything special in Boston. Arrive at the airport in time to check-in, get your boarding passes and check your luggage (yes, you can check luggage through to your final destination - Buenos Aries), pass through the TSA checkpoint and proceed to your gate. Make sure you have your passport handy at check-in since the agent will want to see it. You'll then board the plane for your flight to Dulles. As far as how much time you'll need in Boston, that will depend on the time of day and day of week you are travelling. You are essentially boarding a Domestic flight in Boston but you make need a few extra minutes at the check-in counter while the agent reviews your travel documents. You can check United's website for recommended times but I'd allow at least 90 minutes since you can never tell how many people may be in line ahead of you in the check-in line or the TSA checkpoint.

You'll deplane in Dulles and proceed to the gate for your connecting flight to Buenos Aries - simple really!

Thanks - that is what I thought. We have all flown a lot but just never with domestic connection to international flight. (It is my 19 year old daughter travelling for 6 months in Argentina - I just get to stay home and enjoy any photos she sends, be happy for her that she is having this adventure, and worry - and also listen to her complain that she has 5 hours to kill at Dulles - just the way the FF ticket worked out and since it is essential she make the flight to Buenos Aires that day, thought 2 hours was cutting it too close)

United is nice at Dulles because you don't have to go through security again at least we did not have to on a SFO-Dulles-Frankfurt-Venice flight bags checked through to Venice but did have to do the passport control etc at Frankfurt.

Even though your first segment is domestic, your are checking in at Boston as an international passenger. Depending on airport facilities, you may not be able to use the curbside bag check and self-check kiosks that are available for domestic passengers. Allow plenty of time in case you have to stand in line inside the terminal to check the bag and have the passport scanned, something I never do for domestic-only travel. The connection at Dulles should be the same as for domestic-to-domestic except that the gate agent may ask to see your passport along with the boarding card.

I've never been able to curbside check-in for the domestic portion of an international flight. I would get there no later than 90 minutes as suggested above as you cannot predict if they'll have the desk and security check staffed properly.

When she gets to her gate for her BA departure have her check in with the gate agent so they can verify her passport and boarding pass info. Sometimes they mark the boarding pass and therefore don't require you to show it again when you board.

Hope she has a fantastic experience in Buenos Aires.

I checked gates for same flights yesterday and arrival from Boston and departure to Buenos Aires are both in Terminal C - and were about 10 gates apart yesterday - so that part should be easy anyway. She leaves in 2 weeks so hard to imagine major changes would be made prior to then.