The minimum check in time for an international flight is one hour and there have been instances where people have got to the check-in 58 minutes before take off and Air France would NOT allow them to board so they do hold steady to that hour.
Normally it is suggested, however, that you arrive 2 hours prior to your scheduled flight departure. Per American Airlines, there are different destinations where an even earlier check in is suggested. These include Mexico, Paris (CDG), some Caribbean countries, Dublin (Ireland), and Canada- all 3 hours. India has a suggested check in time of 3.5 hours.
See related link for more information.
At least three hours, but you are safest to contact the airline you are flying on to ask about the specific airport.
The flight time from Cancún International Airport to Cuscatlán International Airport is 1 hour, 5 minutes.
The flight time from Edinburgh Airport to Poznań-Ławica Airport is 1 hour, 42 minutes.
The average flight time from Los Angeles International Airport to Nashville International Airport is 3 hours, 36 minutes.
The flight distance from Cairo International Airport to Jomo Kenyatta International Airport is 2,193 miles / 3,529km with a flight time of approximately 4 hours, 23 minutes.
The flight time from Pittsburgh International Airport to Auckland Airport is about 17 hours.
The flight time from Raleigh-Durham International Airport to London Heathrow Airport is about 7.5 to 8 hours.
The average flight time from Seychelles International Airport to Beijing Capital International Airport is 9 hours, 53 minutes.
The flight time from John F. Kennedy International Airport to Cancún International Airport is about 3 hours, 7 minutes.
The flight time from Toronto Pearson International Airport to Los Angeles International Airport is about 4 hours, 21 minutes.
The flight time from John F. Kennedy International Airport to Honolulu International Airport is 9 hours, 58 minutes.
The flight time from London Heathrow Airport to Indianapolis International Airport is 8 hours.
The flight time from Logan International Airport to Cancún International Airport is: 3 hours, 28 minutes