Baggage allowances are determined by the airlines and will depend on a number of factors, for example, the fare paid, class, route, aircraft type, government regulations, and the airlines' own company, commercial and health and safety policies.
In general, airlines set a "free baggage allowance". The allowance will be expressed by "weight" and by "piece". Airlines may allow, and set charges, for baggage not meeting these criteria, i.e. "excess baggage". Travellers are advised to verify baggage allowances with the relevant airline when booking their ticket to avoid confusion or complications when checking in at the airport.
Baggage handling and delivery is the responsibility of the airlines from the point of check-in to the point of collection. If anything is left on an aircraft the airline should be contacted immediately.
Some airlines subscribe to a replacement service for baggage which has been damaged in transit. For details please contact your airline directly.