Local airports are usually very fast to depart and arrive (having in mind to check-in in time). Don't cut it too close, once I was denied boarding when I should not have been (last flight for the night, they wouldn't wait for me and the plane left 10 min earlier). You will always have time before departure, unless there's been some problem and a long line waiting for check-in.
International are usually fast to depart too (less than an hour after check-in). When arriving it may take 2 hours or more, long lines for passport control and then a line for customs (there are forms to fill and hand to the official, and rarely they select people to search their luggage). Usually there are a lot of intercontinental flights arriving early in the morning)