Useful load
Useful load is the difference between an aircraft's empty weight and its maximum take-off weight: the total it can carry in fuel, people and baggage combined. Because fuel is part of it, a jet cannot have both full tanks and a full cabin on many types; the marketing brochure's range figure usually assumes only four passengers. As a rough guide count 200 lb (90 kg) per adult with a bag, so eight passengers with luggage is about 1,600 lb that comes straight off the fuel available. When an operator says a particular aircraft cannot do your trip non-stop with your group, this is the number they are looking at.