How do you hide a drop of water? By submerging it in a torrential downpour. If there is only one airplane flying in the sky each day, then people on the ground will keep watching that one airplane. But if there are ten or even twenty airplanes flying overhead every day, then no one will bother to look up at these things that have become commonplace.
Thus, when the larger, more capable, and even safer C-130 transport planes began their transport missions in the sky, nobody realized that the Great Tang Empire had begun using more advanced transport planes on a large scale.
However, it is regrettable that these planes are actually not qualified "personnel" transport planes; their base is that of a transport plane, not like the C-47, which was developed from the DC-3 passenger plane conversion.
