The manner in which loads are to be packed and unpacked for an air-borne operation is fully as important as the weight to be carried by available aircraft. Some items, though not too heavy, may be too bulky to be loaded; again, if the plane is to carry bicycles or passengers, obviously it may not carry its maximum tonnage. Speed in deplaning is so essential in most air-borne operations that it is rather unusual to load a Ju-52 to anything like its weight-carrying capacity. It has been said that the outstanding advantage of the Ju-52 and the Ju-90 is that their trapdoors can be opened almost as wide as the aircraft on either the top or the bottom of the fuselage.