Why do we have to weight your luggage in the airport?

All aircraft have a certain weight limit that must not be exceeded for safety reasons. By figuring the number of people and luggage items the plane will carry, the airline can decide what the maximum weight for each bag can be. If a piece of luggage exceeds this weight, or if there are excess luggage items, it may have to be sent out on another flight, which is more costly. This is why you may be charged a fee for bringing more than a few pieces of luggage or having luggage that weighs more than a certain amount.