Airlines routinely sell more seats than are available on flights (factoring in a certain number of no-shows), however if all passengers show for a flight, airlines have no choice but to bump people from flights.

• Before you volunteer to be bumped from a flight, make sure you're clear on the specifics of your compensation such as free flights or cash make sure you are confirmed on the next flight be sure to ask the airline for as many amenities as possible while you wait for the next flight,  include meals, phone calls, hotel rooms, and transfers to and from the airport if you're stuck overnight.

• When airlines bump passengers, they begin with the people who checked in last.

• Airline personnel are required by law to ask for volunteers to be bumped before they start choosing people to bump. 

• Reconfirming domestic flights is not mandatory anymore, but always call your airline to reconfirm international flights