Why Do Passengers Need To Get To The Airport Early & Observe Boarding Times Even When Flights Are Late?

How early one needs to get to the airport before departure depends on whether one is on a domestic or an International Flight. It has been a staple view that one needs to arrive at the airport three hours before departure if you are scheduled for an international flight. For Domestic Flights, one should arrive two hours prior to departure, though people wonder if we should arrive at the airport so early.