Originally Posted by
merrickdb
45 minutes should be fine (I'd probably do 30). If you're checking a bag, you might want to allow 60 minutes.
That's poor advice, depending on the airline. For example, United has a 60-minute cutoff at NRT for both checked bags and check-in. And, that's being at the front of the line and being checked in with the bag tag printed by the computer by 60 minutes sharp before departure. You
may be able to make that deadline if your train arrived 75 minutes before departure and there's no line at the check-in counter, but there's no margin for error.
I think targeting an airport arrival no later than 2 hours before departure is sensible. This strikes a balance between not having a lot of extra time at the airport yet still having time to deal with unexpected things that might happen (long line at check-in, delayed bus, or whatever).