I have read that 3 hours before scheduled take-off was the general rule of thumb for international flights. Someone recently told me that it really depends on the Airport you are flying out of, rather than the airline. Is this true? Would you suggest contacting the airport or the airlines? (Our flight originates Louisville, KY and we are not familiar with the airport.) Thanks.
This is from the Louisville Airport website:
Arrive an hour and a half prior to the scheduled departure time, as most airlines require passengers to check baggage at least 30 minutes prior to departure and be at the gate at least 20 minutes prior.
Please note that at some major airports, passengers must now check baggage 45 minutes prior to departure. Check with your airline as you make your travel plans.
I used to fly out of Nashville and for International I would arrive around two hours in advance. You need a few extra minutes because most of the time you can't use the Kiosk's (there are some that read passports, but....) and the airlines now have VERY FEW live bodies to check you in.
Louisville is probably the same as Nashville. If you aren't used to an airport two hours is a good rule of thumb to prevent panic.
I know fly out of ATL. Yes, I arrive 3 hours in advance. International check in here on Delta is a NIGHTMARE!
I would error on the very conservative side - 3 hours is generally the time given for international flights to/from the U.S. The later you arrive, the less time you have for unexpected delays, lines as security, extra security checks etc. If you cut time short and anything goes wrong, it would be very unpleasant. Much better to spend extra time reading a book by the gate rather than panicking in a security line etc.