C´mmon, you don´t remember in Aliens 2, when RIPLEY whent back to get the child, and she brought Hicks wounded back to the dropship? She placed him in a bed, in the sickbay. Then she loaded up on weapons and ammo, and went for the girl. There was a round table, where they sit and eat. There´s the room with the guns. This all takes place on the upper level of the dropship. The lower level packs the APC, on a ramp that lowers with 4 hidraulic jacks. But the APC is stored inside during the flight. Now, the APC is over 2 meters high,plus the wheel´s height right? Add the upper level, another 2 meters, at least, right? That´s at least 4 meters. Add the floors, about 10 inches thick, each. Wich means more 30 inches to add to the 4 meters we had. This adds to +5 meters, at least, from top to bottom, right? Now look at the cockpit, where we see the co-pilot and pilot. The cockpit takes about 2/3 of the ships hull height, and is supposed to be located on the upper level. Now you tell me, where in hell do you fit a 2,5 meters high APC, and plus all the engines and machinery?
I don´t know. Maybe my english isn´t good enough to explain this right. Maybe i should just write in my native tongue and have you look the translation in Babelfish... But i do know how to measure things. And i do have a sense of scale.
One of the priorities of movies is to fool the public into believing things that are not true. Maybe you are all believing too hard in this...