Originally Posted by
Steve M
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).
The OP did say he would have already checked in online, so there's no check-in constraint. I've found Japanese airports to have the most efficient check-in and security procedures of any country's airports and gate agents tend to be very tolerant of late arrivals. I've checked in at T-15 for domestic flights without any problems.
I recognize I'm more aggressive than most, but many posters have suggested two hours to have time to shop in the airport, relax, have a final meal, and exchange currency. I, and I suspect many others, don't want to do any of those things in the airport and would prefer to spend as little extra time in airports as possible, so a schedule built to allow time for those things isn't really relevant. And even when security is at the gate, I've never known any airline to require you to be at the gate anywhere near 45 minutes before departure. I've never understood how folks religiously adhere to suggestions to arrive two hours before a flight without noticing that they then spend 90 minutes just sitting around in the airport before each flight.