Posted June 19th, 2017, 12:50 PM
...and on another flight from LAX to Canada we were told by the airport that we needed to be there 3 hours in advance as it was international
I'll put my retired airline employee hat on again and say if you really mean you were told by the airport as opposed to told by the airline, then its' meaningless. Airport authorities love to say stuff like that but it's meaningless as here in the U.S., airports don't set airline policies nor do they have any staff to enforce any of the stuff they say. But usually being government bodies, they want to feel important to they say all this stuff that's completely meaningless and is at best, for this situation the worst of the recommended times of all carriers. The airport is just the landlord. If you were going to some other business, do you listen to the business's staff or the landlord (building owner)?
One reason foreign carriers say things like three hours* is to spread the workload. They don't want to staff to process the entire passenger load of their one flight a day at (to them) a small foreign station in 30 minutes so they tell you to arrive 3 hours early so they can spread the workload over two hours. They think it's better to have you wait in line than adequately staff. If you show up three hours before departure, you're likely to be in line for 90 minutes to two hours and you think "yup, needed to be there three hours early". And if you show up 75 minutes before departure, the line has largely been worked off and you wait is five to 15 minutes.
For the airline I used to work for, with the exception of some very specific overseas destinations, there is very little difference between how domestic and international departures are handled other than document checks. The TSA process will be the same - TSA pays no attention to what your destination is. And once you're past TSA, all that's left to do is board.
* A recent flight had typical media saying, for some reason, airport officials recommend arrive three hours early (even for domestic). I had a 6:00am flight and can assure you there would be no one there to check you-in at 3:00am. I left home at my usual 4:00am, parked off-site, and still had plenty of time to get breakfast in the club before going to the gate (no checked bags and TSA Pre-Check).
(screen name is "el"-stone19, not "eye"-stone19)
Regal Princess 9/9/17 British Isles and Norway Passage (Transatlantic)
Regal Princess 10/22/16 NYC/Canada 5-day
Regal Princess 6/14/16 Baltic
Coral Princess 12/23/03 Panama Canal partial transit
Coral Princess 12/24/02 (cancelled - ship delivery delayed
Dawn Princess 6/01 Voyage of the Glaciers N/B
Sky Princess 5/93 Voyage of the Glaciers N/B
Southward 12/92 Pacific Coast 3-day
Seaward 12/90 Western Caribbean