a major portion , if not the whole , of passenger facilities are located underground to reserve a virtually building - free ground level for the most efficient movements of aircraft . a number of pairs of parked positions of aircraft for loading / unloading are arranged in each of a number of rows . adjacent aircraft face in opposite directions to facilitate loading / unloading from and to a pair of passenger gates located below each pair of such parked positions and to also facilitate forward movement of aircraft to and from such parked positions . the resulting arrangement is compact and allows efficient movement of aircraft to and from runways while also minimizing the distances passengers travel in moving from a terminal to gates and in moving from one gate to another . loading / unloading ramps are moveable between inactive positions out of the paths of aircraft and active positions for loading and unloading . two such ramps can be provided for fore and aft loading of one aircraft .