This baggage is limited by airlines with regards to size, weight and number, usually dependent upon the fare paid or class of travel concerned. Baggage exceeding these limits is regarded as excess baggage.
Should passengers having checked baggage not arrive at the departure gate before the flight is closed, the passenger will be offloaded from the flight and baggage must be retrieved from the aircraft hold before the flight is permitted to be dispatched. This is the cause of many delays but is necessary for security reasons to prevent baggage being checked-in without the passenger physically being onboard the same aircraft.