Involuntary Bumping
Most airlines select the passengers to be bumped on the basis of "last to the gate,
first to be bumped". Even if you get to the airport early and have a seat assignment,
arriving late at the gate makes you a prime candidate for bumping.
If it's vital that you be on a flight, be at the gate before boarding starts, usually 20
minutes prior to departure time. This is particularly important at peak times (7-9 a.m.
and 5-7 p.m.). For international flights, most airlines require that you arrive at the
airport at least 2 hours prior to departure to check your baggage and complete the
pre-boarding process. It is wise to be at the gate waiting during this time as well, as
many specific announcements pertaining to your flight are broadcast only at the gate,
and may be missed otherwise.